III. Put in (to be) in the correct form. 1. I... a schoolgirl. 2. Nina and Lena ... sisters. 3. This... a blue dress. 4. The dress andthe shirt... in the wardrobe. 5. The cat... in the yard. 6. You... students. 7. Tom... six. 8. The trees... green. 9. This... a big room. 10. We... brothers.