用所给动词的适当形式填空。
1. I saw the boy ________ (play) football when I looked out of the window.
2. It’s important ________ (not give) goldfish too much food.
3. Children shouldn't spend too much time ________ (watch) TV.
4. Are they busy ________ (count) the birds?
5. My parent _________ (clean) the house at eight yesterday evening.
6. Look! The children _________ (plant) flowers.
7. If anybody _________ (break) the model plane, he ________ (have) to pay for it.
8. Suzy, _________ (not be) late for school.
9. Tom _________ (begin) to learn Chinese last year.