4: Write questions with How long.......? and answer with for or since.

VD: 1) I'm a teacher. I started teaching last year.

How long have you been a tacher?

Since last year. / For a year.

2) I live near the coast. I moved there three years ago.

-How long have you lived near the coast?

-For three years

3) I'm married. I got married two years ago.

-How long have you been married?

For two years

4) I know Mary. We first met last Christmas.

-How long have you known Mary?

since last Christmas

5) I work in a factory. I started working there in 1994.

How long have you worked in a factory?

since 1994

6) I play the piano. I had my first lesson in 2001.

-How long have you played the piaon?

Since 2001

7) I've got a passport. I got it three years ago.

How long have you got a passport?

For three years

It's everyone's duty to keep the enviroment clean

=>..............Keeping the enviroment clean is everyone's duty.........

điền mạo từ thích hợp “a/an/ the hoặc x (không cần mạo từ)” vào chỗ trống:

1. There was ___a_____knock on __the______door. I opened it and found ____a____small dark man in __a______blue overcoat and ___a____woolen cap.

2. He said he was ___an_____employee of _____the___gas company and had come to read ___the_____meter.

3. But I had ___a_____suspicion that he wasn't speaking ____the____truth because _____x___meter readers usually wear ____x____peaked caps.

4. However, I took him to ___the_____ meter, which is in ____the____dark corner under ____the____ stairs.

5. I asked if he had ____a____ torch; he said he disliked torches and always read _____x___ meters by ____the____light of ___a_____match.

6. I remarked that if there was ___a_____leak in ____a____ gas pipe there might be ____an____ explosion while he was reading ___the_____meter.

7. He said, “As ____a____matter of ____x____fact, there was ___an_____explosion in ____the____last house I visited; and Mr. Smith, ____the____owner of __the______house, was burnt in ___the_____face.”

8. “Mr. Smith was holding ____a____lighted match at ___the_____time of __the______explosion.”

9. To prevent __a______possible repetition of this accident, I lent him ___a_____torch.

10. He switched on ___the_____torch, read ___the_____meter and wrote ___the_____ reading down on ___the_____back of _____an___envelope.

11. I said in ____x____surprise that _____x___meter readers usually put _____the___readings down in __a______book.

12. He said that he had had ___a_____book but that it had been burnt in ___the_____fire in____x____ Mr. Smith's house.

13. By this time I had come to ___the_____conclusion that he wasn't ____a____genuine meter reader; and ____the____moment he left ___the_____house I rang _____the___police.

1/ I’d prefer a salad to a cooked meal.

-->I’d rather ______a salad than a cooked meal______

2/ Tan Phuoc hadn’t made a speech before, so he is very nervous.

--> Because Tan Phuoc wasn’t used _______to make a speech, he is very nervous______

3/ When my father was young, he usually sang very well in a rock band.

--> When my father was young, he used to ________sing very well in a rock band._______

theo bài gọi tuổi em hiện nay là 4.a tuổi thì

tuổi em trước đây (lúc anh bằng tuổi em hiện nay) sẽ là a tuổi

từ đó đến nay tuổi mỗi người tăng thêm là: 4a - a = 3a

do đó tuổi anh hiện nay là 4a + 3a = 7 a

khi em bằng tuổi anh hiện nay thì tuổ mỗi người lại tăng thêm: 7a - 4a = 3a

 tuổi hai anh em khi đó là: (7a+3a) + (4a + 3a) = 17a và bằng 51 tuổi

tuổi em hiện nay: 51/17 *4 = 3*4=12 (tuổi)

tuổi anh hiện nay: 51/17 *7 = 3*7 =21 tuổi

3n=3n-3+3

3n-3 chia hết cho n-1 

để 3n chia hết cho n-1

suy ra 3 chia hết cho n-1

suy n -1 thuộc {+_1;+_3}

suy ra n thuộc {-2;0;2;4}

đề thiếu 

diện tích của hình bình hành bằng tích của canh đáy và chiếu cao 

công thức  a xh

a: đáy

h: chiều cao

a.He set off alone a month ago and ( 1.not,hear ) ..didn't hear.............. of since . He ( 2.fall)...was fallen... in to river and (eat)....eaten...... by crocodiles , or ( kidnap)...kidnaped....... by tribes men , or ( catch ) .......caught... fever and (die)...died....... of it

b. it's not much use ( have) ..to have...... a bike if you don't know how ( ride ).....to ride.... it

c. try ( avoid) .......(be)...to avoid being....... late . He hates ( keep) .keeping. ( wait)....to wait....