用所给词的适当形式填空。 1. We think she (be)a good singer in the future. 2. What you (do) at 4:30 p.m. yesterday? 3. I ( shop)in a supermarket when you called me up. 4. the dog (lie) under the tree when you passed? 5. While it ( rain) heavily,he went out. 6. The train usually (leave) the station at ten o'clock in the morning. 7. Look! The girls ( dance) there.