用单词的适当形式填空。

1. Some people call the brain a _______ computer. (live)

2. We need a _______ on this project by next week. (decide)

3. It is quite difficult for the old to fell _______ sometimes. (sleep)

4. "2012"was one of my _______ films which were on in 2009. (favour)

5. Who first _______ the system of numbers from 1to 9?  (invention)

6. The old woman and her grandson finished their breakfast _______. (silent)

7. "Xin Hai" ship and its 25-member crew were saved to _______. (free)

8. The moon was an _______ area before the two American astronauts landed on it. (explore)