Ⅱ.完成句子
1．They were in time to produce carbon, nitrogen, water vapour and other gases, ______________________(这些后来就形成了地球的大气层). (atmosphere)
答案 which were to make the earth's atmosphere
2．______________________(它们突然灭绝的原因) still remains a mystery.(disappear)
答案 Why they suddenly disappeared
3．______________________(随着火箭的升空), we were pushed back into our seats because we were trying to escape the pull of the earth's gravity. (air)
答案 As the rocket rose into the air
Ⅲ.模仿造句
1．What it was_to_become was uncertain until between 4.5 and 3.8 billion years ago.
[翻译]年轻时，他不知道自己后来会成名。
答案 As a young man, he didn't know he was to become famous later.
2．This produced a chain reaction，which made_it_possible_for_life_to_develop.
[翻译]太阳照射地球，这使得人们有可能种植作物。
