用括号内所给动词的适当形式填空。
1. Jack, one of my buddies, kept ________ (nod) his head as if he completely understood what I said.
2. Years ago we didn't know this, but recent science _________ (show)that people who don't sleep well will soon get ill.
3. He with his friends ________ (lie) in the sun and feeling relaxed on the Long Beach when his new boss called him.
4. We first met on a train in 2000. We both felt immediately that we ______ (know)each other for years.
5. Listen to the speaker carefully, or you __________ (miss) something important .
6. - The food here is nice enough.
- Yes,my friend ____________ (introduce) me a right place.
7. Jack told me that they ________ (return)to the USA from Shanghai by the end of next November.
8. To prevent the things getting worse, action should ___________ (take) at once.