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.
As a result of pollution, Lake Erie, on the borders of the USA and Canada, is now without any living things. Pollutions in water are not simply a matter of “poisons” killing large numbers of fish overnight. Very often the effects of pollution are not noticed for many months or years because the first organisms to be affected are either plants or plankton. But these organisms are the food of fish and birds and other creatures. When this food disappears, the fish and birds die in this way a whole food chain can be wiped out, and it is not until dead fish and water birds are seen at the river’s edge or on the sea shore that people realize what is happening. Where do the substances which pollute the water come from? There are two main sources – sewage and industrial waste. As more detergent is used in the home, so more of it is finally put into our rivers, lakes and seas.
Detergents harm water birds dissolving the natural substance which keep their feather waterproof. Sewage itself, if it is not properly treated, makes the water dirty and prevents all forms of life in rivers and the sea from receiving the oxygen they need. Industrial waste is even more harmful since there are many high poisonous things in it, such as copper and lead. So, if we want to stop this pollution, the answer is simple, sewage and industrial waste must be made clean before flowing into the water. It may already be too late to save some rivers and lakes, but others can still be saved if the correct action is taken at once.
Pollution in water is noticed ______.
A. when the first organisms is affected
B. as soon as the balance of nature is destroyed.
C. when poisons are poured into water
D. when a good many fish and birds die
Đáp án D
Ô nhiễm chỉ được chú ý tới ______.
A. khi sinh vật đầu tiên bị ảnh hưởng.
B. ngay sau khi sự cân bằng tự nhiên bị phá hủy.
C. khi chất độc bị đổ xuống nguồn nước.
D. khi nhiều loài cá và chim bị chết.
Dẫn chứng câu 3-5 đoạn 1: “Very often the effects of pollution are not noticed for many months or years because the first organisms to be affected are either plants or plankton. But these organisms are the food of fish and birds and other creatures. When this food disappears, the fish and birds die in this way a whole food chain can be wiped out, and it is not until dead fish and water birds are seen at the river’s edge or on the sea shore that people realize what is happening” – (Những tác động thường xuyên của ô nhiễm không được chú ý tới trong vài tháng, thậm chí là vài năm bởi sinh vật đầu tiên bị ảnh hưởng chỉ là các loài thực vật hoặc các sinh vật phù du. Nhưng đối với những sinh vật làm thức ăn cho cá, chim hoặc và loài sinh vật khác. Khi chúng biến mất thì cá, chim cũng chết theo như cách mà 1 chuỗi thức ăn bị xóa sổ, và cho đến khi xác chết chim, cá được nhìn thấy trên mặt hồ hoặc bờ biển thì con người mới nhận thức được rằng điều gì đang xảy ra).