3. 选C。根据第二段The library will continue its usual hours during the week, but have shorter hours on Saturday and Sunday.这一句可以推断出正确答案。

2. 选B。 根据第二段buses going to the town center will leave the main hall every hour on the half hour during the day.可以得出正确答案。

20. 选B。 advice是不可数名词 suggestion是可数名词　 书面英语要用written English。

19. 选A。every time 用作连词，意为“每一次”。

18. 选D。　 阻止某人做某事可用stop/prevent somebody (from )doing something 或 keep somebody from doing something。

17. 选C。　 听从某人的意见要用follow/take one’s advice。

16. 选C。　 do you suppose 是插入语。

15. 选D。 share是“共享”，spare 作动词是“抽出时间”。

14. 选A。　 reason后要用for。was 后引导的是表语从句用 that。

13. 选C。　 some…last week 是个定语从句修饰the school。