用所给动词的适当形式填空。 1. If it _____ (not rain), we will go for a picnic. 2. Look at the children! They _____ (play) happily. 3. Don't forget _____ (return) the book to Tom when you finish it. 4. Our geography teacher once told us that the earth _____ (go) around the sun. 5. He likes collecting all kinds of information. I often see him _____ (search) the Internet. 6. —Where is Mr. White? I haven't seen him for a few days. —He _____ (go) to Hong Kong. 7. —I'm too tired. —So am I. We'd better stop _____ (walk) and have a rest. 8. —Do you like listening to popular songs? —Sure. My family _____ (be) all music lovers (爱好者). 9. The summer holidays are coming. I _____ (fly) to the Hainan Island with my parents. 10. —Sally, your dress looks so nice! —Thank you. It _____ (make) of silk.