1. Mai is not strong enough to lift that box.
2. They have worked here since last year.
3. Sue goes shopping in order to buy a new  television.
4. Harry is going to buy a new house next week.
5. The teacher said Jack that he should do his homework more carefully.
6.  Going?????
7.His father asked him to turn down the radio for him.
8,Ba always studies very well.
9. The young mother told her little son not to be cruel to animals.
10. Mrs.Nga asked Nam to tell the whole story again.
11. My father did not use to smoke 10 years ago.
12. How about going to the movies now?
13. My father drives carefully.
14.Your house is smaller than mine.
15. Lan has studied English for 4 years.