g) x³-27y³= (x-3y)(x²+3xy+9y²)

h) 64 + 8x³=(4+2x)(16+8x+4x²)

1)

a) 4y²-4xy+x²= x²-4xy+4y²= (x-2y)²

b) 9x²-12xy+4y²= (3x)²-2.3x.2y+(2y)²= (3x-2y)²

c) 16x²-25=(4x)²-5²= (4x-5)(4x+5)

d) 1-9y²= 1²-(3y)²=(1-3y)(1+3y)

a) Xét ΔDEF vuông tại D

→EF²=DE²+DF²(định lí pytago)

→EF²= 5²+12²

→EF²= 25+144

→EF²=169

→EF²=13(cm)

Vậy EF=13(cm)

didn't take - went

1 It's the first time we have seen the car

2 It's the first time we have gone there

3 It's the first time they have performed here

4 It's the first time Nam has held a girl's hand

5 It's the first time Duy has read this kind of story

1. You have a toothache because you eat too much candy.

2. I have more free time on Sunday so we can go to the zoo.

3. You should eat less fast food.

4. Today I am going to school, but my brother isn't going.

5. Sports, such as running and riding a bike, need a lot of calories.

6. My mom wants to be healthier, so she eats more fruits and vegetables.

7. You should come back home early because it's cold outside.

8. I don't want to be tired tomorrow. I should go to bed early.

9. Mai has to try to talk less because she has a sore throat.

10. It's harmful to your body if you go to bed late.

1.was discovered

2.the room is cleaned every day.

3.all flights were cancelled

4.this road is not used very often.

5.the computer is being used at the moment.

6.a new hospital has been built near the airport.

7.you will be asked a lot of questions at the interview.

8.Ann wasn't offered the job.

9.was stolen.

10.has been learnt.

1 arranging

2 swimming

3 to be

4 to force - doing

5 driving - riding

6 doing

7 to stop talking

8 help - to get

9 seeing - working

10 to borrow

11 processing

12 watch - rehearsing

13 destroying

14 playing

15 to help - prepare

1.  Children often want their parents to buy them comics and sweets.

2.  Many doctors advise their patients to avoid eating food high in fats.

3. I don't like staying at home all weekend.

4.  Health experts regularly remind us to do exercise once every day.

5. The parking attendant didn't allow the woman to park for free.

6.  We must learn to live together as brothers.

7. I'd like to enjoy spending more time with the hopeless children.

8. We don't mind getting up earlier than usual for work..

9.  I decided to open new branches in mountainous areas.

10. Why don't you make some suggestions instead of complaining?

11.  It's necessary to make careful plans.

12. I'd like to go somewhere this summer.

13.  I can feel something crawling up my leg.

14.  He preferred being good than seeming good.

15. She would have got a better chance of job if she had studied English well.

Bài 2

1)Tessa wants to buy a new coat soon.

2)We must avoid wasting so much time

3)Sometimes a country refuses participating the olympics

4)I meant to give Judy a nice welcome yesterday.

5)I like seeing the rocky mountains some days

6)I always  like to see my doctor once a year

7)I can't stand getting up at five/tomorrow

8) The buses usually stop running before midnight

9)My father seems to get better/now

10) Last year we made an agreement to work together.

joyful