Ответ:

I. 1. Is

  2. were

  3. isn't

  4. wasn't, am

  5. are.

II. 1. What did you read yesterday?

   2. What have they bought today?

   3. Does she like ice-cream?

   4. Nick and Mike don't learn at school.

   5. Where do they live?

III. 1. never left

    2. is travelling

    3. ran

    4. is reading