One of the most urgent environmental problems in the world today is the shortage of clean water. Having clean drinking water is basic human right. But acid rain, industrial pollution and garbage have made many sources of water undrinkable. Lakes, reservoirs and even entire seas have become vast pools of poison. Lake Baikal in Russia is one of the largest lakes in the world. It contains a rich variety of animals and plants, including 1,300 rare species that do not exist anywhere else in the world. But they are being destroyed by the massive volumes of industrial effluent which pours into the lake everyday. Even where law existed, the government did not have the power to enforce them. Most industries simply ignore the regulations. The Mediterranean Sea occupies 1% of the world’s water surface. But it is the dumping ground for 50% of all marine pollution. Almost 16 countries regularly throw industrial wastes a few miles off shore.
Water is free to everyone. A few years ago people thought that the supply of clean water in the world was limitless. Today, many water supplies have been ruined by pollution and sewage. Clean water is now scarce, and we are at last beginning to respect this precious source. We should do something now.
1. According to the writer, one environmental problem in the world today is ________ .
A. acid rain B. industrial pollution.
C. safe water shortage. D. population explosion .
2. Many sources of water are not drinkable because of _______ .
A. acid rain. B. industrial pollution.
C. garbage D. all A, B, C, are correct
3. What is serious problem of Lake Baikal in Russia?
A. It contains a rich variety of animals and plants.
B. It is polluted by massive volumes of industrial wastes discharged into it .
C. It has 1,300 rare species that do not exist anywhere else in the world .
D. The government did not have the power to enforce laws and regulations.
4. How many countries throw industrial waste into the Mediterranean Sea regularly?
A. nearly 16 B. exactly 16.
C. exactly 15 D. less than 15.
5. What is the message to the reader?
A. We should take action to protect our water resources.
B. We should take all water resources into account.
C. We should limit the use of water resources.
D. We should encourage people to use safe water.
Vấn đề 8. Một container có hình khối có kích thước như trong hình. Các thùng có 54 lít nước trong đó. Bình muốn biết một xô đầy chứa bao nhiêu lít nước , do đó, ông đổ cả xô nước vào container và thấy rằng mức độ của nước tại 7 8 là chiều cao của container. Từ đó, ông có thể tính toán bao nhiêu lít nước một xô đầy chứa . Nếu container rỗng , bao nhiêu xô nước phải Bình đổ vào các container để làm cho nó đầy đủ?
To solve this problem, let's break it down step by step.
Step 1: Calculate the volume of the cuboid container.
The volume of a cuboid is given by the formula:
Volume = Length × Width × Height
Given:
Length = 12 meters
Width = 6 meters
Height = 4 meters
Volume = 12 × 6 × 4 = 288 cubic meters
Step 2: Convert the volume to liters.
Since 1 cubic meter = 1000 liters, we have:
Volume = 288 × 1000 = 288,000 liters
Step 3: Determine the volume of water after pouring a full bucket.
The water level after pouring the bucket is at 7/8 the height of the container, which means the volume of water is 7/8 of the volume of the container.
Volume of water = (7/8) × 288,000 liters = 252,000 liters
Step 4: Calculate the volume of water in one bucket.
Since initially, there were 54 liters in the container and after pouring the bucket, there were 252,000 liters, the volume of water in one bucket can be found by subtracting the initial volume from the final volume.
Volume of water in one bucket = 252,000 liters - 54 liters = 251,946 liters
Step 5: Determine how many buckets are needed to fill the container.
To find out how many buckets are needed to fill the container, divide the volume of the container by the volume of water in one bucket.
Number of buckets needed = 288,000 liters / 251,946 liters ≈ 1.144
Since Bình cannot pour a fraction of a bucket, he would need to pour 2 buckets of water to fill the container completely.