6. Professor Li has solved the ________(难题) and everyone is cheering.

7. Mars'________(万有引力) is only about 38% of Earth's.

8. Raising your child to tell the difference between right and wrong is one of the f________ tasks of parenthood.

9. Air pollution will get worse and this will be _______ to people, for example, it can cause cancer.

10. Last night we had a discussion, which became more and more _________. Finally we reached an agreement that we will never use ________ whatever happens. (violent)

【答案】

1. system　 2. climate　 3. theory　 4. laying　 5. exists

6. puzzle　 7. gravity　 8. fundamental　 9. harmful 10. violent; violence

【解析】本题主要考查重要词汇的用法。

【经典句式】

1. It exploded loudly with fire and rock, which were in time to produce the water vapour, carbon dioxide, oxygen, nitrogen and other gases, which were to make the earth' s atmosphere. 它与火和岩石一起猛烈地爆炸，这些物质及时产生水蒸汽、二氧化碳、氧、氮和其他气体，这些气体会形成地球的大气层。

2. That made it possible for life to begin to develop. 那使得生命的初始发展成为可能。

3. But when I tried to step forward I found I was carried twice as far as on the earth and fell over.

但当我试图前进时，我发现我被抬到在地面上的两倍，跌倒了。

4. The earth became so violent that it was not clear whether the shape would last or not.

地球晃动剧烈，不清楚地球是否能够维持它的形状。

翻译下列句子。

1. 既然你的工作已经做完了，最好休息一下吧。