Here are the correct words to complete the sentences:

1. That
2. This
3. Do you like (these)
4. I love (these) shoes but I don't like (that) shirt.
5. What are the answers to (these) questions?
6. Let’s watch a movie (this) is a good idea.
7. This book isn’t very good, but (that) book’s great.
8. Whose house is (this)?
9. How much is (that) T-shirt?
10. How much is (those) shoes?
11. Excuse me, how much is (that) shirt?
12. I like that skirt. Do you have (that) in black?
13. Do you have (these) shoes in black?
14. I like these shorts. Can I try (these) on?
15. What size are (those) pants over there?
16. How much is (that) shirt by the window?
17. (This) new book "I learn Smart World 6" is very good.
18. (Those) machines sell well.
19. My brother can use (them).
20. This T-shirt is nice. I want to try (it).

For the second exercise:
1. This
2. (my)
3. (your) book
4. Music is (my) favourite subject.

Feel free to ask if you need any more help!