4.going　词组look forward to中的to是介词，后面应跟动词ing形式作宾语。

3.giving　动词consider后面跟动词?ing形式作宾语。

2.has had 　由for about five years 可知，这里用现在完成时。

10. -When _______ you _______ (visit) the Summer Palace?

-Last month.

答案：1.have packed　由already提示可判断，这里用现在完成时。

9. -Where is Tina and Amy?

-They _______ (go) to the reading?room.　

8. The students think understanding their roots _______ (help) them understand themselves.　

7. They went to China _______ (see) the Great Wall last spring.　

6. The famous film stars _______ (appear) on CCTV next month.　

5. _______ (visit) their ancestors' villages is one of the highlights of the journey.　

4. The poor child looked forward to _______ (go) to school.