`1.` How many teachers are there in your school?

`2.` Does your sister go to school on foot everyday?

`3.` I spend two hours doing my homework every night.

`->` It takes sb time to do sth : ai đó mất bao lâu để làm gì

= Sb spend time doing sth : ai đó dành bao lâu để làm gì

`4.` Tung is the most intelligent in our class.

`5.` How heavy is your son ?

`6.` Why don't we sing and dance.

`->` How about = what about + Ving

= why don't we/you + Vinf

`7.` I'm the strongest in my school.

 1 How many teachers are there in your shool?

2 Does your sister go to school on foot every day?

3 I spend two hours doing my homework every night.

4 Trung is the most intelligent student in my class.

5 Why don't we sing and dance? 

6 I am the strongest student in our class.