a)(x+5)(2x-3)=0

=> x+5=0 hoặc 2x-3=0

=>x=-5 hoặc x=3/2

b)(x^2+1)(6x+3)=0

=>x^2+1=0 hoặc 6x+3=0

=>x=-1 hoặc x=-1/2

c)2(x+3)(x-4)=0

=>2x+6=0 hoặc x-4=0

=>x=-3 hoặc x=4

Ex4:Choose the correct answer to complete the following sentences.

1.He didn't dare (leave) the house because he was afraid of meeting someone who might recognize him.

2.I know my hair needs (cut) but I never have time to go to the hairdresser's.

3. He was fined for (exceed) the speed limit.

4.Please go on (write).

5.The doctor advised gim to give (smoke).

6.I didn't feel like (work),so I suggested (spend) the day in garden.

7.She has her mother (wash) her clothes.

8.I wasted hours (look) for this book.

9.It is a good idea for you (leave).

Ex4:Choose the correct answer to complete the following sentences.

1.We watched the children (jump) from a window.

2.It's isn't good for children (eat) too many sweets.

3.I am sorry for (be) late.

4.I used (ride) a lot but I haven't had a chance to do any since coming here.

5.(Beat) by a bee, his baby cried loudly.

6.He made me (repeat) his instructions five times.

7.She apologized for (borrow) my motorbike without asking for permission.

8.She told me (look) through her correspondence.

9.She claimed........to tell the future by gazing in to her crystal ball.

A.be able            B.to be able           C.being able          D.been able 

10.You'll never regret (do) a kind action.

11.The police accused him of (set) fire tho the building.

12.(Bring) up by uncle, he became a good person.

13.I distinctively remember (pay) him.I gave him $2.

14.It is very unpleasant (wake) up and hear the rain outside.

15.He decided (put) the broken glass on top of his wall to prevent boys climbing over it.

Ex4:Choose the correct answer to complete the following sentences.

1.He is thinking of (leave) his job and going to America.

2.I hate(go) to work in the rain.

3.(chase) by a dog,he ran as quickly as possible.

4.Would you mind ( show) me how to up erate the machine?

5.After (read) this article you will give up smoking.

6.I tired (explain) to him but he went on grumbling.

7.Try to forget it.It doesn't worth (worry) about it.

8.There are people who can't help (laugh) when they see that man.

9.I caught him (climb) over my wall.

10.Ask him (come) in don't keep him standing at the door. 

Ex3:Write sentences using cue words:

1.He/interes/find/a new job.

2.Read/poetry/be/favorite free time activity.

3.You/good/fix things?

4.He/used/using the Internet.

5.I/remember/see/him/TV several times.

6.You/afraid/ride/busy streets?

Bài 1:Gerund or infinitive?Give the correct verb form. 1.Please remember (turn off) the radio before you go out. 2.It was very kind of her ( lend) you the money.                                                         3.(Eat) a lot of vegetables is very necessary for everyone.                       4.The students often collect waste paper for(recycle).                                                5.I can't stand (travel) by underground. 6.Do you mind (open) the door for me?       7.Don't try ( persuade) me.Nothing can make me ( change) my mind.    8.I like (think) carefully about things before (make) decision.   9.Our head teacher makes us (wear) jackets-even in summer. 10.He tried (deny) (take) the money,but nobody believed him.