21．While he was investigating ways to improve the telescope, Newton made 　　　discovery　 which completely changed　　　 man’s understanding of color．

　　　 A．a；／　　 　　　　　 B．a；the　　 　　　　　 C．／；the 　　　　　　 D．the；a

7．所有志愿者都在参加严格培训，为这次大型的国际会议做准备，因为他们代表的是中国。

　 　All the volunteers are 　　　　in strict training in 　　　　　for the important international　 conference because they　　　 China.

6．越来越多的学生不顾他们父母的反对，正在考虑出国留学。

　 More and more students are giving　　　 to studying abroad 　　　of their parents’　 opposition．

5．为迎合她对歌剧的偏爱，他送给她一张歌剧图兰朵的票作为生日礼物。

　 To　　　 to her　　　 for opera, he gave her a ticket for Tulando as a birthday present.

4．这个文化遗址的历史可以追溯到9世纪，从建筑的角度来看，它保存完好。　

　　 　　　back to the 9^th century, this historic site，in　　　 of its buildings，is in good　　 .

3．现在我们用大量的塑料制品代替木制品使得更多的森林受到了政府的保护。

　 Now we　　　 plastic goods for wooden goods so that more forests are　　　 the 　　　of　 the government.

2．虽然这次的会议记录未必和我们会上所说的话完全一致，但我们已经达成一致意见。

　 　Although the written record of our meeting dose not necessarily 　　　　　　　what was　 actually said，we have reached a　　　　 .

1．对我而言，他不仅仅是一位老师，他是我真正的朋友，因此，在这件事情上他有发言权。

As far as I'm　　　 , he is　　 　　　　　a teacher. He is my true friend．So，he has a　　 in this matter.

7．To our surprise, he’s got rid of the bad habit in such a short time.

　　 　　　　makes us 　　　　is that he’s 　　　　himself 　　　　　the bad habit in such a short time.

6．We built a monument in honor of those heroes who gave their lives to defend our country.

　　 We built a monument in honor of those heroes who gave their lives 　　　　　　　　　　　　

our country.