OLM cung cấp gói bải giảng điện tử PPT cho giáo viên đầu năm học

Thi thử và xem hướng dẫn giải chi tiết đề tham khảo 12 môn thi Tốt nghiệp THPT 2025

Tham gia cuộc thi "Nhà giáo sáng tạo" ẫm giải thưởng với tổng giá trị lên đến 10 triệu VNĐ

Mini game 20/11 tri ân thầy cô, nhận thưởng hấp dẫn - Tham gia ngay!

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Mua vip
★·.·´¯`·.·★ 𝑀𝓇𝓈.𝒲𝒽𝒶𝓁𝑒𝐹𝒾𝓈𝒽 ★·.·´¯`·....
29 tháng 10 2019 - olm

Dịch cái

Control by Nine Tailet Fox 

I saw the camera and no one suvivor 

We donated the alpha T 90 seconds. All suvivors go to the helicopter nearby to escape facility 
#Toán lớp 7
4
IT
♡ηảη♡ (๖team lion๖)
29 tháng 10 2019

dịch

Kiểm soát bởi Nine Tailet Fox
Tôi đã nhìn thấy camera và không có ai sống sót
Chúng tôi tặng alpha T 90 giây. Tất cả những người sống sót đến trực thăng gần đó để thoát khỏi cơ sở

Đúng(0)
#𝒌𝒂𝒎𝒊ㅤ♪
29 tháng 10 2019

Dịch

Kiểm soát bởi Nine Tailet Fox
Tôi đã nhìn thấy camera và không có ai sống sót
Chúng tôi tặng alpha T 90 giây. Tất cả những người sống sót đến trực thăng gần đó để thoát khỏi cơ sở

Hk tốt :)

Đúng(0)
LQ
Lê Quỳnh Anh
31 tháng 7 2018
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42. HISTORY OF THE HELICOPTER Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

Why was Paul Cornu’s flight important?

A. It was the first practical helicopter flight.

B. It lasted 7 minutes and 40 seconds.

C. It was the first time a helicopter lifted into the air without ground assistance.

D. It was the first time a helicopter lifted into the air.
#Mẫu giáo
1
DH
Dương Hoàn Anh
31 tháng 7 2018

Đáp án C


Đáp án nằm ở dòng 1 + 2 đoạn 3: “On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance”

Đúng(0)
LQ
Lê Quỳnh Anh
14 tháng 12 2017
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.HISTORY OF THE HELICOPTERAlthough first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

 

Why was Paul Cornu’s flight important?

A. It was the first practical helicopter flight

B. It lasted 7 minutes and 40 seconds

C. It was the first time a helicopter lifted into the air without ground assistance

D. It was the first time a helicopter lifted into the air
#Mẫu giáo
1
DH
Dương Hoàn Anh
14 tháng 12 2017

Đáp án C

Đáp án nằm ở dòng 1 + 2 đoạn 3: “On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance”

Đúng(0)
DM
Dương Minh
4 tháng 11 2019
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.HISTORY OF THE HELICOPTERAlthough first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

Why was Paul Cornu’s flight important?

A. It was the first practical helicopter flight.

B. It lasted 7 minutes and 40 seconds.

C. It was the first time a helicopter lifted into the air without ground assistance.

D. It was the first time a helicopter lifted into the air.
#Mẫu giáo
1
NH
Nguyen Hoang Hai
4 tháng 11 2019

Đáp án C

Đáp án nằm ở dòng 1 + 2 đoạn 3: “On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance”

Đúng(0)
NM
NGUYỄN MINH QUÂN
4 tháng 8 2019 - olm
strange thing in my mother .i am completely addicted to the game and you know all parents don`t like this.My mother is also among them.she always take my phone when i play, then hide it in a place just she know .when i free .i try to find the place she hide my phone ,but fail. I just know she hide my phone in the storehouse.in the evening ,i sat on the chair and think how to know the place my mother hide phone .After 10 munites ,i think a nice idea i can take my camera and put it on the...
Đọc tiếp

strange thing in my mother .

i am completely addicted to the game and you know all parents don`t like this.My mother is also among them.she always take my phone when i play, then hide it in a place just she know .when i free .i try to find the place she hide my phone ,but fail. I just know she hide my phone in the storehouse.in the evening ,i sat on the chair and think how to know the place my mother hide phone .After 10 munites ,i think a nice idea i can take my camera and put it on the storehouse and i can know the place my mom hide my phone .at 21;30pm .i go downstair and quietly go to the storehouse then i put a camera on the old desk .next morning i go to the storehouse ,watch the camera then i can take my phone and i go to school .in the afternoon,i go home my mother open the door and take my phone .after 15 minutes ,she go out of the storehouse .next i go to the storehouse and watch the camera.i see the door of the storehouse open but no one go inside i watch it for 15 times then i wash my face and watch it again but just like last time ,no one go inside then i ask my mother did she go inside and she answer she is go to the storehouse .if the camera can not turned ny mom,this is so impossed.i feel afraid because my camera my dad bought it yesterday it very new why .... why .now i will never turn my mom never

mk mới đọc chuyện này ngày hum qua bn nào vietsub hộ mk với....

 
#Tiếng anh lớp 7
1
TN
Thiên Nhi ♥.♥
4 tháng 8 2019

tôi hoàn toàn nghiện các trò chơi và bạn biết tất cả các bậc cha mẹ ko thích nó. Mẹ tôi cũng là một trong những người đó .Cô luôn lấy điện thoại của tôi khi tôi chơi, sau đó giấu nó ở một nơi chỉ cô biết Khi tôi phóng .Tôi thử để tìm ra nơi cô giấu điện thoại của tôi, nhưng thất bại. Tôi chỉ biết cô ấy giấu điện thoại của tôi trong nhà kho .Vào buổi tối, tôi ngồi trên ghế và suy nghĩ làm thế nào để biết nơi mẹ giấu điện thoại của tôi .Sau 10 phút đi, tôi nghĩ rằng một ý tưởng tốt đẹp tôi có thể lấy máy ảnh của tôi và đặt nó trên kho và tôi có thể biết nơi mẹ tôi giấu điện thoại của tôi .10 h sáng , tôi đi xuống cầu thang và lặng lẽ đi đến kho sau đó tôi đặt một camera ở mặt cũ buổi sáng bàn .Sau đó , tôi đi đến kho, xem camera sau đó tôi có thể lấy điện thoại của tôi và tôi đi học .Vào buổi chiều, tôi về nhà mẹ tôi mở cửa và lấy điện thoại của tôi .Sau 15 phút, cô đi ra khỏi kho.Tiếp theo tôi đi đến kho và xem camera.Tooi nhìn thấy cánh cửa của kho mở nhưng không ai đi bên trong . Tôi xem nó cho 15 lần sau đó tôi rửa mặt và xem nó một lần nữa nhưng cũng giống như lần trước, không ai đi vào bên trong sau đó tôi hỏi mẹ tôi đã làm cô đi vào trong và cô trả lời cô đang đi đến kho .Nếu camera không thể quay mẹ của tôi, điều này thật quan trọng . Tôi sợ vì máy ảnh của tôi cha tôi đã mua nó ngày hôm qua nó rất mới tại sao ... . tại sao .Bây giờ  tôi sẽ không bao giờ quay mẹ tôi nữa , không bao giờ

Đúng(0)
DM
Dương Minh
8 tháng 4 2019
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.HISTORY OF THE HELICOPTERAlthough first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

Why was “dissymmetry” important to the early pioneers of helicopter flight?

A. It was an effect that caused helicopter to crash.

B. It equalized lift on each side of the central shaft.

C. It allowed helicopters to lift from the ground.

D. It allowed the rotor blade angles to be altered.
#Mẫu giáo
1
NH
Nguyen Hoang Hai
8 tháng 4 2019

Đáp án A

Tại sao “tính không đối xứng” lại quan trọng với những chiếc máy bay trực thăng trước đây
Đáp án nằm ở dòng 3, 4 và 5 đoạn 2: “Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.”

Đúng(0)
LQ
Lê Quỳnh Anh
7 tháng 6 2018
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.HISTORY OF THE HELICOPTERAlthough first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

 

Why was “dissymmetry” important to the early pioneers of helicopter flight?

A. It was an effect that caused helicopter to crash

B. It equalized lift on each side of the central shaft

C. It allowed helicopters to lift from the ground

D. It allowed the rotor blade angles to be altered
#Mẫu giáo
1
DH
Dương Hoàn Anh
7 tháng 6 2018

Đáp án A

Tại sao “tính không đối xứng” lại quan trọng với những chiếc máy bay trực thăng trước đây
Đáp án nằm ở dòng 3, 4 và 5 đoạn 2: “Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.”

Đúng(0)
LQ
Lê Quỳnh Anh
16 tháng 7 2019
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42. HISTORY OF THE HELICOPTER Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

Why was “dissymmetry” important to the early pioneers of helicopter flight?

A. It was an effect that caused helicopter to crash.

B. It equalized lift on each side of the central shaft.

C. It allowed helicopters to lift from the ground.

D. It allowed the rotor blade angles to be altered.
#Mẫu giáo
1
DH
Dương Hoàn Anh
16 tháng 7 2019

Đáp án A

Tại sao “tính không đối xứng” lại quan trọng với những chiếc máy bay trực thăng trước đây
Đáp án nằm ở dòng 3, 4 và 5 đoạn 2: “Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.”

Đúng(0)
DM
Dương Minh
29 tháng 11 2017
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.HISTORY OF THE HELICOPTERAlthough first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

Why is it important that lift be equal on both sides of the helicopter shaft?

A. If there is more lift on one side, the helicopter will flip.

B. Equal lift means that the helicopter will be faster.

C. Dissymmetry of lift makes helicopters fly well.

D. It allows the rotor blade angles to be changed.
#Mẫu giáo
1
NH
Nguyen Hoang Hai
29 tháng 11 2017

Đáp án B

Đáp án nằm ở dòng 3, 4 và 5 đoạn 2: “Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.”

Đúng(0)
LQ
Lê Quỳnh Anh
19 tháng 4 2017
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42. HISTORY OF THE HELICOPTER Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

HISTORY OF THE HELICOPTER

Although first flight generally attributed to a fixed-wing aircraft, the helicopter actually represents the first style of flight envisioned by humans. The ancient Chinese developed a toy that rose upward when spun rapidly. As early as the mid-sixteenth century, the great Italian inventor Leonardo da Vinci had drawn a prototype for the machine that we now know as the helicopter.

Early in the twentieth century, a great deal of experimentation and revision was taking place with regard to helicopter flight. The well-known phrase “two steps forward and one step back” provided an apt descriptor for early flight development. Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.

On November 13, 1907, the French pioneer Paul Cornu made history by lifting a twin-rotor helicopter into the air for a few seconds without ground assistance. Several models followed without significance until in 1924 when another French pioneer, Etienne Oehmichen, became the first to fly a helicopter for one kilometer. It was a historic flight of 7 minutes and 40 seconds. By 1936, solutions have been found to many of the problems with helicopter flight.

With the introduction of the German Focke-Wulf Fw 61, the first practical helicopter became a reality.

Why is it important that lift be equal on both sides of the helicopter shaft?

A. If there is more lift on one side, the helicopter will flip.

B. Equal lift means that the helicopter will be faster.

C. Dissymmetry of lift makes helicopters fly well.

D. It allows the rotor blade angles to be changed.
#Mẫu giáo
1
DH
Dương Hoàn Anh
19 tháng 4 2017

Đáp án B


Đáp án nằm ở dòng 3, 4 và 5 đoạn 2: “Uneven lift, known as dissymmetry, caused the early helicopters to flip over and confounded the inventors until the creation of the swash-plate; this allowed the rotor blade angles to be changed so that lift would be equal on each side of the shaft.”

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