1+1=?
thanks
K
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12 tháng 2 2022
1. - Peter: - “How are you today, Mary?” - Mary: - “__________”
A. Thanks B. No, thanks C. Fine, thanks D. Yes, thanks
2. Mr. Brown__________ as a doctor since 2016.
A. worked B. has worked C. works D. have worked
3. He is the__________ student in die class, base on his high grade.
A. smartest B. smarter C. smart D. more smart
4. I am the boy__________ is wearing a white T-shirt.
A. whom B. which C. whose D. who
5. It all depends__________ my parents. Anyway, we'll keep in touch.
A. in B. at C. of D. on
6. He never eats fish, __________?
A. doesn't he B. does he C. isn't he D. did he
7. The telephone__________ by Alexander Bell.
A. invented B. invent C. was invented D. is invented
8. If you work hard, you__________ in the final examination.
A. will succeed B. succeed C. would succeed D. had succeeded
9. The doctor suggested that his patients__________ smoking.
A. stopping B. to stop C. should stop D. stops
10. - Nam: - “That's an excellent story, Lan” - Lan: - “__________”
A. Never mind B. It's kind of you to say so
C. No, thanks D. Don't say so
MN
12 tháng 2 2022
1. - Peter: - “How are you today, Mary?” - Mary: - “__________”
A. Thanks B. No, thanks C. Fine, thanks D. Yes, thanks
2. Mr. Brown__________ as a doctor since 2016.
A. worked B. has worked C. works D. have worked
3. He is the__________ student in die class, base on his high grade.
A. smartest B. smarter C. smart D. more smart
4. I am the boy__________ is wearing a white T-shirt.
A. whom B. which C. whose D. who
5. It all depends__________ my parents. Anyway, we'll keep in touch.
A. in B. at C. of D. on
6. He never eats fish, __________?
A. doesn't he B. does he C. isn't he D. did he
7. The telephone__________ by Alexander Bell.
A. invented B. invent C. was invented D. is invented
8. If you work hard, you__________ in the final examination.
A. will succeed B. succeed C. would succeed D. had succeeded
9. The doctor suggested that his patients__________ smoking.
A. stopping B. to stop C. should stop D. stops
10. - Nam: - “That's an excellent story, Lan” - Lan: - “__________”
A. Never mind B. It's kind of you to say so
C. No, thanks D. Don't say so
11. I am__________ that people have spoiled this area.
A. disappointed B. disappointment C. disappointing D. disappoint
12. Hoa failed her math test.__________, she has to do the test again.
A. However B. Because C. Moreover D. Therefore
13. I wish_______an astronaut on the future
A. were B. to be C. would be D. will be
14. Let’s wait for them here. I’m sure that they will _____soon.
A. turn off B. turn up C. turn down D. turn over
15. Mr. and Mrs. Blake were delighted when they _____to sell their house so quickly.
A. succeeded B. could C. risked D. manage
16. The man asked me .....................
A. where had I gone the previous day. B. where I had gone the previous day.
C. where I had gone yesterday. D. where did I go yesterday.
17. Jenny refused to explain the reason ..................... her absence from class last week.
A. why B. about C. for D. of
18. The party was great! Everyone enjoyed ..................... very much.
A. themselves B. ourselves C. oneself D. itself
19. Nguyen Du is considered one of the best ..................... that Vietnam has ever produced.
A. poets B. poems C. poetry D. poetic
21. Please don't put much salt in the soup. Just ......................
A. few B. a few C. a little D. little
22. The police are looking for the man ..................... car was found in the jungle last night.
A. whose B. whom C. who D. his
23. It is high time we.....................something to protect rare animals from extinction.
A. did B. do C. will do D. are doing
24. Despite working in the same office, Mary earns ..................... her boyfriend.
A. twice as many as B. twice more than C. twice as more than D. twice as much as
25. Jack never helps his mum with the housework,.....................?
A. does he doesn't he C. will he D. did he
26. When the boy was told that he had failed the exam, he was extremely .....................
A. disappointing B. disappointedly C. disappointed D. disappointment
27. "No, you are not allowed ..................... out tonight, Mike," the father said angrily.
A. to go B. going C. to going D. go
28. "The room is too dirty! Do you think it needs...................., honey?" said the wife.
A. to clean B. cleaning B. to be cleaning D. cleaned
29. I think your health will not improve ..................... you give up smoking.
A. if B. when C. unless D. until
30. Can you close the gate ..................... the hens will not go out?
A. so as to B. in order to C. in order for D. so that
TT
2
AH
Akai Haruma
Giáo viên
25 tháng 9 2023
Lời giải:
Gọi tổng trên là $A$
$A=\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{18.19.20}$
$2A=\frac{2}{1.2.3}+\frac{2}{2.3.4}+\frac{2}{3.4.5}+...+\frac{2}{18.19.20}$
$=\frac{3-1}{1.2.3}+\frac{4-2}{2.3.4}+\frac{5-3}{3.4.5}+....+\frac{20-18}{18.19.20}$
$=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+\frac{1}{3.4}-\frac{1}{4.5}+...+\frac{1}{18.19}-\frac{1}{19.20}$
$=\frac{1}{1.2}-\frac{1}{19.20}=\frac{189}{380}$
$\Rightarrow A=\frac{189}{760}$
ND
1
NA
Ngoc Anh Thai
Giáo viên
11 tháng 4 2021
\(A=\dfrac{1}{2}.\dfrac{2}{3}.\dfrac{3}{4}...\dfrac{2010}{2011}=\dfrac{1}{2011}\)
NM
12 tháng 9 2023
Ta có:
\(\left(2x+1\right),\left(2y-1\right)\inƯ\left(15\right)=\left\{\pm1;\pm3;\pm5;\pm15\right\}\\ \Rightarrow\left(2x+1\right),\left(2y-1\right)\in\left\{\left(1,15\right);\left(15,1\right);\left(-1,-15\right);\left(-15,-1\right);\left(3,5\right);\left(5,3\right);\left(-3,-5\right);\left(-5,-3\right)\right\}\)
\(\Rightarrow x,y\in\left\{\left(0,10\right);\left(7,3\right);\left(-1,-5\right);\left(-8,2\right);\left(1,5\right);\left(2,4\right);\left(-2,0\right);\left(-3,1\right)\right\}\)
ND
1
1 + 1 = 2
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1 + 1 = 2 .