17. over the years 很多年来，常与现在完成时连用如：

　　 Over the years, they’ve planted many trees on the hills.

多年来他们已在山上种植了许多树。

16. on display 展览

15. known adj. 有名的 著名的　 know v. 知道 认识

14. be sure to do 一定做某事 肯定做某事 如：

　 It is sure to snow. 肯定要下雪

　 Be sure not to forget it. 千万不要忘记呀!

13. fun n. 有趣　 funny adj. 有趣的

12. though == although 作连词　 虽然，尽管

放在句子中间/句首，不能和but 连用

Though it was very late, he went on working. 虽然很晚了，但他还在工作

Mr. Smith , though he was young, did it very well.

史密斯先生虽然年轻，却做得很好。

11. look for 寻找

　 My pen is lost. Could you help me look for it?

我的笔丢了。你能帮我找一下吗？

10. unfortunately adv. 不幸运地　　 fortunately adv. 幸运地

9. be important to sb. 对…重要

　 be important for sb. to do. 做某事对某人很重要

8. clear adj. 清楚的，清澈的　 clearly　 adv. 清楚地