Ка определить центр масс различных тел и фигур
формула​

1. Where's Ann? Have you seen HER?

2. Where are my keys? Where did I put THEM?

3. That is not my bag, MINE is black.

4. This letter is for Bill. Can you give it to HIM?

5. We wrote to John but he didn't answer OUR letter.

6. “I can't find my pen. Can I use YOURS?” “Yes, of course.”

7. We're going to the cinema. Why don't you come with US?

8. Can we use your washing machine? OURS is broken.

9. Did your sister pass HER exams?

10. Tom invited some friends of HIS to the restaurant.

11. Some people talk about THEIR jobs all the time.

12. Last night I went out for a meal with a friend of MINE.

13. We had dinner with a neighbour of OURS.

1. What is in the room? Where is her desk? 
2. What is old?
3. Who is in the classroom? Where are you? 
4. Who will be ready soon? When will they be ready?
5. Who was a post-graduate last year? When was she a post-graduate? 
6. What will be over tomorrow? When will the work be over? 
7. Who was ready to begin the work? What were they ready to begin? 
8. Where were you last week? When were you at the University?
9. What is in the note-book? Where is the next text? 
10. When will they be students?
11. What is this ancient monastery now?