Ответ:
exercise 1
1. You are not eating my lunch.
2. He is not playing the clarinet.
3. I am not wearing new glasses.
4. We are not coming to the party.
5. They are not talking about the homework.
exercise 2
1. are you sitting
6. Sarah is taking
7. Are they leaving
8. am doing
9. Is he phoning
exercise 3
1. trousers
2. shorts
3. T-shirt
4. shorts
10. pyjamas
exercise 4
1. dark
11. smart
12. long-sleeved
13. patterned
14. tight