1. It is important to do 做某事很重要
2. It is necessary to do 做某事有必要
3. It is possible to do 做某事可能
4. It is hard to do 做某事困难
5. It takes sb some time to do 做某事花时间
6. It costs sb money to do 做某事花钱
7. It is said that 据说
8. It is reported that 据报道
9. It seems that 似乎
10. There is no doubt that 毫无疑问
11. There is no need to do 没必要做
12. There is something wrong with ……出问题
13. There used to be 过去有
14. used to do 过去常常
15. be supposed to 应该
16. had better do 最好做
17. would like to do 想要做
18. be allowed to do 被允许做
19. be made to do 被迫做
20. be seen to do 被看见做
21. ask sb to do 让某人做
22. tell sb to do 告诉某人做
23. allow sb to do 允许某人做
24. help sb (to) do 帮助某人做
25. encourage sb to do 鼓励某人做
26. teach sb to do 教某人做
27. warn sb to do 警告某人做
28. advise sb to do 建议某人做
29. invite sb to do 邀请某人做
30. order sb to do 命令某人做