Mr. David said, "I played badminton yesterday." → Mr. David said that he         badminton the day before.

Tom                     that his mother was in hospital.

I wondered                     the right thing.

if I am doing                         B. was I doing

The teacher said, "I didn't see her." →  The teacher said                  her.

A.he had seen                       B. I hadn't seen

He asked me when                     there.

A.did I arrive     B. will I arrive      C. I had arrived              D. I can arrive

He said that Ha and his friend               married           .

A.were getting / tomorrow             B. are getting / the next day

C. were getting/ the next day          D. will get/ the day after

 She told me                     her up at six o'clock.

Mai asked Quang                        .

A.when he will come back                 B. when he would come back

C. when he comes back                  D. when he is coming back

Mary said she                     there the day before. 

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.