Ms Nga wanted to know what time                   .

A.the movie began                         B. the movie begins

C. does the movie begin                 D. did the movie begin

The stranger asked me where I                    from.

Nghiệm pt sin2x-cos2x=0

Tập xác định của hàm số y=2cosx-1/sinx

Phương trình Sin2x=cosx có nghiệm là:

Quy đồng mẫu 2 phân thức sau:

$\frac{{\mathrm{x}}^3}{{\mathrm{x}}^3-3{\mathrm{x}}^2\mathrm{y}+3{\mathrm{xy}}^2-{\mathrm{y}}^3}$ ; $\frac{\mathrm{x}}{{\mathrm{y}}^2-\mathrm{xy}}$

Cho hàm số y = -2x^2 + x +2 / 2x + 1 . Mệnh đề nào sau đây đúng :

A. Hàm số không có cực trị 

B. Hàm số có cực tiểu bằng -6

C. Hàm số có cực đại bằng 1

D. Hàm số có cực tiểu bằng -3

Người ta điều chế khí N2 từ phản ứng nhiệt phân muối amoni đicromat theo phương trình (NH4)2Cr2O7 → Cr2O3+ N2+ 4H2O. Biết khi nhiệt phân 32 gam muối thu được 20 gam chất rắn. Hiệu suất của phản ứng này là:

câu này giải bảo toàn khói lượng thê nào ạ

Peptit A có phân tử khối là 245 và chứa 17,14% nitơ về khối lượng. Khi thủy phân không hoàn toàn A, trong hỗn hợp sản phẩm thu được có hai đipeptit B và C. Phân tử khối tương ứng của B và C là 174 và 188. Câu tạo thu gọn của A là?

"Don't make noise because I am doing my homework now"

A.  He asked me not to make noise because I am doing my homework now.

B.  He asked me not to make noise because I was doing my homework then.

C.  He asked me not to make noise because he was doing his homework then.

Mai said that "I haven't seen Tuan since last month."

A.  Mai said she doesn't see Tuan since the previous month.

B.  Mai said she wasn't seen Tuan since the previous month.

C.  Mai said she hasn't seen Tuan since the previous month.

D.  Mai said she hadn't seen Tuan since the previous month.

"He is talking to your sister", Lan said to me.

A.  Lan told me he was talking to your sister.

B.  Lan told to me he was talking to my sister.

C.  Lan told me he was talking to my sister.

D.  Lan told me she was talking to her sister.

"I wrote to her yesterday." He said

A.  He said to me I wrote to her the day before.

B.                              He told me he wrote to her yesterday.

C.  He told me he had written to her yesterday.

"I'll tell you about this tomorrow, Daisy." said Peter.

A.  Peter said to Daisy that he will tell her about that the next day.

B.  Peter told Daisy that I would tell you about that the next day.

C.  Peter told Daisy that he would tell her about that the next day.

Mr Ha told me that he would meet me the                              day

I wonder                          we'll catch the bus                we'll walk to school.

A.  if / and whether                     B. whether / or that

Minh  him up when the bus came there.

A.  told her wake                        B. asked her to wake

I asked her                              , but she said nothing

A.  what the matter was              B. what was the matter

She asked me                          I                    or not.

A.  If / had busy                          B.Whether / was busy

C. If / has been busy                  D. Whether / busy

He asked his mother what                                               .

A.  time was it                             B. time is it

Lan:" Why don't you study hard for the exam, Nam?"

A.                              Lan advised me not to study hard for the exam

B.  Lan advised me to study hard for the exam

C.  Lan advised Nam not to study hard for the exam

D.  Lan advised Nam to study hard for the exam.

He said "If I had enough money, I could buy that house."

A.  He said if he had enough money, he could buy that house.

B.  He said if he had had enough money, he could buy that house.

C.  He said if he had enough money, he could have bought that house.

Miss Lan said to hlm,"Why are you so late? Did your car have a flat fire?"

A.  Miss Lan told him why was he so late and did your car have a flat fire

B.  Miss Lan asked him why was he so late and did your car have a flat fire.

C.  Miss Lan asked him why was he so late and if your car have a flat fire.

"He is talking to your father", She said to me.

A.  She told me he was talking to your father.

B.  She told me she was talking to my father.

C.  She told me he was talking to my father.

He (A) advised her (B) thinking about that example (C) again because it needed

Rút gọn các biểu thức sau

a> x(2x^2-3)-x^2(5x+1)+x^2

b> 3x(x-2)-5x(1-x)-8(x^2-3)

2cos2x-${\cos }^2\frac{x}{2}$-$10\cos (\frac{5\pi }{2}$$-$$x$)+$\frac{7}{2}$=$\frac{1}{2}\cos x$

I. Choose the best answer (A, B, C or D) to complete each of the following sentences. 

1. Would you like ………….some coffee?

A. drink                         B. to drink           C. drinks              D. drinking

2. It’s the house…………..window is painted white.

A. whose                       B. which              C. that                  D. what

3. I suggested…………..in my car.

A. go                              B. to go                C. goes                 D. going

4. “I don’t want to go anywhere today,” he said; “I’d rather ………..at home.”

A. stay                           B. have stayed     C. stayed              D. will stay

5. The whole report is inaccurate. ……………, it’s difficult to read.

A. Although                  B. Such                C. Moreover        D. As a result

6. …………people understand the difference.

A. Few                           B. Little               C. Not                  D. Much

7. How many car………in this factory every year?

A. make                         B. makes              C. making            D. made

8. Summers are hot, with………average above 26 .

A. month                       B. monthly           C. each                 D. every

9. Between the two stories, this one is…………

A. funnier                      B. funniest           C. the funnier      D. the funniest

10. When I came home yesterday, my mother…………….dinner.

A.is cooking                  B. was cooking    C. cooked             D. has cooked

11…………..the job, I know how difficult it is.

A. To do                        B. To have done  C. To be doing     D. Doing

12. They ………….entirely by self-interest

A. motivate                   B. are motivated  C. was motivate   D. are motivating

13. The floorboards were replaced prior to…………of the sale.

A. complete                   B. completion      C. completing      D. completed

14……………if I wanted to drink beer or wine.

A.I knew                        B. We told           C. They asked               D. She said

15. His friends described him as an …………person

A. easy-going                B. easy-go            C. going-easy                D. go-easy

Giúp mk với ạ!

I. Choose the word whose underlined part is pronounced differently from that of the others by circling the letter A, B, C or D

1. A. cleaned                 B. caused             C. decided           D. studied

2. A. chemist                 B. cheap               C. chair                D. child

3. A. fashion                 B. nature              C. planet              D. sand

4. A. boxes                    B. watches           C. glasses            D. loves

5. A. celebrate               B. comic              C. city                  D. exciting

II. Choose the word that has a different stress pattern from that of the others by circling the letter A, B, C or D. 

1. A. appliance              B. effective                   C. adventure        D. average

2. A. device                   B. pilot                 C. absent              D. happen

3. A. exchange              B. travel               C. replace            D. collect

4. A. invitation              B. celebration      C. economic         D. experience

5. A. document              B. reference         C. pedestrian       D. energy

Giúp mk với ạ!

They will have the car repaired soon.

A.  They will have someone repair the car soon.

B.  The car will repair soon.

C.  They themselves will repair their car soon.