Cho hình lăng trụ đứng có đáy là một hình vuông cạnh a và chiều cao bằng 4a. Tính diện tích S của mặt cầu ngoại tiếp hình lăng trụ đó.

A. 12 πa 2

B.  18 πa 2

C.  9 πa 2

D.  15 πa 2

Một hình hộp chữ nhật có chiều dài 15dm, chiều rộng 5dm, chiều cao 4dm. Vậy thể tích của hình đó là

A. 300 m 3

B. 300 d m 3

C. 30 d m 3

D. 3 d m 3

Tìm x biết  x   :   - 1 3 2   =   - 1 3

A.  1 3 3

B.  - 1 3 3

C.  1 3

D.  - 1 3

The old man ______ to hospital early. I think they did it too late

A. must have taken

B. should have taken

C. must have been taken

D. should have been taken

We _______ touch since we _______ school three years ago.

A. lost / have left

B. have lost / leave

C. have lost / left

D. were losing / had left

Choose the word (A, B, C or D) that best fits the blank space in the following passage.

One of the (13) _______ things that can happen on our earth is an earthquake. When earthquakes take place near large cities, many people may be killed and many buildings are (14) _______ down. Fire may start and (15) _______ more damage than the quake itself. Earthquake comes (16) ______ a shaking of the rocks under the surface of the earth. Forces within the earth push against the rocks until they break. We cannot tell exactly (17) _______ an earthquake is coming, but we can know places on the (18) _______ where they happen most often.

Điền vào số 13

A. bad

B. badly

C. worse

D. worst