21. Einstein developed __________(理论)of relativity.

15．转折点____________________　　 20.worm virus ________________

14．登陆，着陆 ________________　　 19.give permission to _________

13．自由勋章___________________　　 18. one giant leap____________

12．试图_______________________　　 17. cut short________________　

11．海军飞行员_________________　　 16. out of control ____________

10. I can’t wait ____ the present box.

　A. open　 B. to open　 C. opening　 D. opened

9. Loud music makes me ____. So I feel very happy.

　 A. energetic　 B. stressed out　 C. energy　　 D. stress out

8. I ____ an expensive gift for my birthday, but I could not ____ it.

　 A. accepted, received　 B. received, accept　 C. accepted, receive　　 D. accepted, received

7. It’s ____ to play on the road. You’d better play in a ____ place.

　 A. safe, dangerous　 B. safety, danger　 C. safe, danger　 D. dangerous, safe