He doesn't know who was the nineteenth president of the United States.
He isn't sure when the Civil War ended.
Seventies:forty three, ten:fifty two, seven:twenty one, zero:forty five ,nineteen:thirty five,twenty three:thirty
2. Is Lisa painting a picture?
3. Are you having a good time?
4. We are playing a game.
5. They are climbing a tree
6. Is Paul eating an apple?
7. I am watching tv
8. Is John driving his car?
1. The dean of our faculty can speak three languages.2. The great Russian mathematician N I Lobachevsky could become a professor in 23 years old yet.3. Oleg tries to translate the text today, because he understands that it is not able to do it tomorrow.4. You have to work hard to become an experienced lawyer5. She should not have to change her flat to country house6. In the spring the children should eat more vitamins7. At the beginning of the year they were supposed go to Spain , but could not8. Children should not watch TV after ten9. You should learn how to cook by yourself10. Has collection already begun? -It Started half an hour ago
1 Yes, he has.
2 Yes, he is.
3 No, it isn't (или Yes, it is)