Điền một từ thích hợp vào mỗi chỗ trống cho đoạn văn sau.
The world’s oceans are so vast that they (71)____ cope with the present level of pollution. However, little is known about the long-term effects of (72)______slow poisoning. The most serious problem of modem time is (73)_____ man is destroying the earth's natural resources and transforming huge areas (74)_____ wasteland. As a result, it is becoming extremely difficult to grow enough (75)____ feed the world’s rapidly increasing population. A way of protecting all the wildlife on the earth must also be found (76)____ many species are in danger of disappearing completely (77)______ the surface of the earth. The dangers, (78)___, are not confined solely to the land and the sea.The smoke in the atmosphere, for example, is increasing so (79)____that the amount of sunlight has reduced in many cities. Man’s (80)_____ environment is being changed in a serious way.
Trả lời câu hỏi dưới đây:
_______(77)