用am, is, are填空。
1. What _____ those? _____ they birds?
2. He _____ my friend. _____ your friend a boy or a girl?
3. This _____ his ruler. Where ______ my ruler?
4. I _____ in Class Three. ______ you in Class Three,too?
5.Those ______ their apples. Where ______ his apples?