I. 1-5. ACABC 6-10. ABBAB 11-15. ACBBA 16-20. CBABB
II. 21-25 CBDCA 26-30 CBBCA 31-35 DDADD
III. 36-40 CDBAD 41-45 BCADB 46-50 ACBDA 51-55 CBCAD
IV. 56-58 CAB 59-62 ABCA 63-66 CBAC 67-70 CDAC
V. 71. Procedure/Course/Steps 72. drive/frighten 73. pray 74. avoid/prevent
75. chosen/selected 76. tigers 77.burned/burnt 78.kneel 79. vivid 80.study
VI. One possible version:
From the picture, we can see that pollution is posing a threat to our earth, which comes in many ways. Millions of chimneys of the factories are pouring heavy smoke into air, which causes serious air pollution. A large amount of waste water from the factories pollutes water, making our rivers fishless and our water unfit to drink and swim in. Furthermore, a lot of trees have been cut down without proper plans, which contributes to the soil being washed away. It seems that we really have no clean place to live.
The pollution is so serious that we have to find effective solutions to it. As far as I am concerned, the government should pass laws to reduce polluted air. Some measures should be taken to purify the water before it is poured into the rivers or the seas. We should plant more trees to keep the soil in place. What’s more, people should be further educated to realize the importance of environmental protection. Thus, we will have a clean and tidy environment.