Here are the best answers to the questions:

1. **Who** ______ those?
**Answer: A. are**

2. This is ______ eraser.
**Answer: B. an**

3. There ______ two windows in the classroom.
**Answer: A. are**

4. There ______ a chair and two tables in the classroom.
**Answer: B. are**

5. Where ______ you? I live in Ha noi.
**Answer: B. are**

6. How ______ do you spell your name?
**Answer: C. do**

7. This is my father. ______ name is Ha.
**Answer: A. His**

8. What ______ is that? - It's a door.
**Answer: A. What**

9. What ______ does your father do?
**Answer: A. does**

10. How old ______ you? - I am ten.
**Answer: A. are**

11. These are my teachers ______ names are Mrs Ha and Mrs Lan.
**Answer: C. Their**

12. What are those? - ______ bookshelves.
**Answer: A. They**

13. Where ______ Minh and Ba?
**Answer: A. is**

14. How many floors ______ your school have?
**Answer: A. does**

15. My sister brushes ______ teeth in the evening.
**Answer: A. her**

16. What ______ did you do yesterday evening?
**Answer: A. did**

17. Is your school in the city ______ in the country?
**Answer: A. or**

18. Ba and Hoa are students. ______ are in the class.
**Answer: A. These**

19. (For this item, context is missing for the question word, so I can't provide an answer. Please clarify if there are specific options.)

Let me know if you need further assistance!