1. This is my computer.   

2. That is your computer.

3. --- Is this a teacher's desk? 

--- Yes, it is.  

4. --- What time is it?  

--- It's two o'clock.

5. It's 9:45. It's time for math class.  

6. --- Is this your T- shirt? 

--- No, it isn't.

7. --- What colour is it? 

--- It's white.  

8. It's warm today. Let's play football.

9. It's cool. Is it cold?  

10. --- How much is it? 

--- It's ten yuan.

11. --- How much are they？ 

--- They're three yuan.   

12. --- Are they ducks?  

--- No, they're aren't. 

13. --- How many horses are there? 

--- Twelve.