Exercise 21 :

1. in order to be : để làm gì.

2. is no point:để làm gì

3. until we finished : cho tới khi chúng tôi ...

5. if she doesn't

-> Câu điều kiện loại 1 : S + Ve.es , s + will / can /may + V

6. what the time 

-> S + asked (sb) + wh-question + s + v(lùi thì)

7. put an advertisement for : làm một quảng cáo

8. finished the speech thanks to 

-> thanks to: nhờ vào

9. was a month since

10. following to their

Exercise 22 :

1. interested in = likes

2. let us park

let sb do sth = allow sb to do sth : cho phép ai là gì

3. if I had seen 

-> S + asked (sb) + if + s + v(lùi thì)

4. there's a hole : có một cái hố

5. called of the match = cancel the match

6. pay attention to = take notice of : chú ý tới cái gì 

7. if I could borrow

8. might have forgotten : có lẽ đã quên

9. effient in checking

10. children have fun 

have fun = enjoy 

Exercise 23 :

1. be produced in this company

2. to talk to him again

3. my holiday 

4. ought to lock 

ought to + V : nên làm gì

5. a chance to

6. from Paul , nobody 

-> apart from : ngoại trừ

7. used to : quen với

8. felt to do : muốn làm gì

9. unable to sing

10. soon our arrival