用所给词的适当形式填空。
1. Before ________ (enter), he nodded to us.
2. She is a ________ (sense) girl, let's help her.
3. He is too short ________ (reach) the window.
4. The baby ________ (wet) its bed already.
5. He was so tired after running that he ________ (lie) on the ground.
6. I feel even ________ (bad) today.
7. Can you ask her ________ us a talk? (give)
8. The river has ________ very dirty. (become)
9. I ________ (phone) you as soon as I ________. (arrive)
10. ________ (cut) down the Christmas tree on the farm is very interesting .