11. domestic a. 本国的，国内的;家用的;家庭的

　　Washington responded by freezing the price of domestic oil.

　　华盛顿作出的反应是冻结国内的石油价格。

　　The store deals in objects of domestic utility.

　　那家商店出售家庭用品。

　　12. constant a. 不变的，恒定的 n. 常数

　　In our world nothing seems constant.

　　在我们这个世界上似乎没有东西是永恒不变的。

　　The speed of light is an important constant.

　　光速是一个重要的常数。

　　13. cliff n. 悬崖，峭壁

　　He couldn't find a hold on the cliff.

　　他在悬崖上找不到一个可以站住脚的地方。

　　The narrow path zigzags up the cliff.

　　这条狭窄的小径曲曲折折地向峭壁伸延。

　　14. authority n. 权威;当局

　　We see him as an authority on the subject.

　　我们把他看作为这方面的权威。

　　The new building must be financed by the local authority.

　　新大楼的建筑资金必须由地方当局提供。

　　15. audio a. 听觉

　　As with visual feedback, computer games tend to excel at positive audio feedback.

　　和视觉反馈一样，计算机游戏擅长于正面听觉反馈。

　　16. attitude n. 态度

　　She shows a very positive attitude to her work.

　　她工作态度非常积极。

　　17. community n. 社区，社会

　　Community colleges have become popular and their enrollments have increased rapidly.

　　社区大学日渐增多，报名人数迅速增长。

　　The welfare of the community is the same as the welfare of its members.

　　社会的福利就等于其成员的福利。

　　18. commit vt. 犯(错误，罪行等)，干(坏事等)

　　They committed outrages on innocent citizens.

　　他们对无辜的市民犯下了暴行。

　　19. comment n. /vt. 评论

　　He made no comments on our proposal.

　　他对我们的建议没有作评论。

　　He commented that it was an excellent film.

　　他评论这电影很精彩。

　　20. distinguish vt. 区分，辨别

　　It's important to distinguish fact from fiction.

　　把现实与虚构区分开来是很重要的。

　　We should distinguish between right and wrong.

　　我们应辨别是非。