1. Mr. Maslov was not answering an enquiry at 10 o’clock in the morning
2. I wasn't having Breakfast at this time on Sunday.
3. he wasn't going through the catalogues when I came into the room.
4. Nina wasn't going to institute when I met her.
5. My friend didn't writing his English exercises while his wife and son were watching TV
6. We didn't discuss prices when you telephoned us.
7 .I didn't translating from Russian into English while Oleg was answering our teacher's questions.
8. They didn't having their English lesson at 9 o’clock yesterday morning.
12. is, is
13. is, is
14. is
15. is, is
16. is
17. is
18. is
19. is
20. is, are, is, is, is, is
Объяснение:
Может я неправильно понял, но здесь слишком много "is"