用括号内所给动词的正确形式填空。

1. Harry Potter is a film that is worth ________ (see) several times.

2. If we don't do anything, the changes ________ (not take) place.

3. When ________ UNICEF ________ (set) up to help governments and families make

    the world a better place for children?

4. Sandy ________ (choose) a tie for her father when she travelled in Shanghai.

5. The story was funny enough ________ (make) all of us laugh.

6. So far, a number of doctors ________ (send) to help the sick people in that area.

什么是风电场？