B. He likes scientific research.

C. He wants to make contributions to the world.

18. What do we know about Copernicus' theory?

A. It concluded that the sun is spinning.

B. It was influenced by Newton and Einstein.

C. It is the basis of ideas about the universe today.

19. What did people believe was the center of the universe during Copernicus' time?

A. The Earth. B. The sun. C. God.

20. Why did Copernicus publish his theory while he was dying?

A. He wasn't sure of his theory until then.

B. He was afraid of being punished.

C. His friends told him not to publish it.

第二部分 完型填空（共20小题；每小题1.5分，满分30分）

阅读下面短文，选出最佳选项，并在答题卡上将该项涂黑。

　　If you are human, you can't help but experience times when everything seems to be going wrong. You must also _21__as if your life is completely out of control at times. It is during those "down times" that words of encouragement from family, friends, co-workers or __22_strangers can boost(增强)your spirits. It is also during those __23_that negative words can be devastating (毁灭性的) and sink you deeper and deeper into depression.

　　For example, consider this story about a group of _24__who were traveling through the woods when __25__of them fell into a deep pit(坑). All of the other frogs gathered around the __26__.When they saw how _27__the pit was, they told the two _28__frogs they would never get out.

The two frogs didn't obey what other frogs said and tried to __29__ out of the pit. The other frogs kept telling them not to jump, _30__it was in vain. Finally, one of the frogs followed what the other frogs were saying and simply __31__. He fell down and _32_. The other frog continued to jump as __33_as he could. Once again the crowd of frogs shouted at him to _34__ the pain. The more they _35__, the harder he jumped and finally he __36__to safety.