Раскройте скобки,употребляя требуюшуюся форму инфинитива 1.He knows mathematics much better than he did last year.He

1. He knows mathematics much better than he did last year. He must have worked a lot in summer. 2.Your mathematics is very poor. You must work at it in summer. 3. Where is Peter?  — Oh, he must be reading in the library. He is getting ready for a very difficult examination. 4. You must have been studying English for several years already. Your language is very good. 5. Oh, look how white and clean everything is! It must have snowed at night. 6. Oh, you are all in snow, you look like a snowman. It must be snowing heavily.7. Look, what huge snowdrifts there are everywhere, and the path is covered with knee-deep snow. It must have been snowing for several hours already. 8. You look fresh! You must have had a good sleep at night. 9. You look very tired. You must have a good sleep at night.