Trong các hình sau, hình nào là hình bình hành?

A. 

B. 

C. 

D. 

Điền số thích hợp vào chỗ trống:

Nowadays, people ____ social networks with more and more caution.

A. uses

B. are using

C. used

D. use

Trong các mệnh đề sau, mệnh đề nào đúng:

A. lim x → − ∞ x 4 − x 1 − 2 x = + ∞

B. lim x → − ∞ x 4 − x 1 − 2 x = 1

C. lim x → − ∞ x 4 − x 1 − 2 x = − ∞

D. lim x → − ∞ x 4 − x 1 − 2 x = 0

Cho hình chóp S.ABCD có đáy ABCD là một hình vuông cạnh a. Các mặt phẳng (SAB) và (SAD) cùng vuông góc với mặt phẳng đáy, cạnh SC tạo với mặt phẳng đáy một góc 60 ° . Thể tích của khối chóp đã cho bằng:

A.  a 3 6 5

B.  a 3 6 3

C.  a 3 6 4

D.  a 3 6 9

Điền số thích hợp vào ô trống:

Giá trị của chữ số 5 trong số 45009 là c

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

For more than six million American children, coming home after school means coming back to an empty house. Some deal with the situation by watching TV. Some may hide. But all of them have something in common. They spend part of each day alone. They are called “latchkey children”. They are children who look after themselves while their parents work. And their bad condition has become a subject of concern.

Lynette Long was once the principal of an elementary school. She said, “we had a school rule against wearing jewelry. A lot of kids had chains around their necks with keys attached. I was constantly telling them to put the keys inside shirts. There were so many keys; it never came to my mind what they meant.” Slowly, she learned that they were house keys. She and her husband began talking to the children who had keys. They learned of the effect working couples and single parents were having on their children. Fear wasthe biggest problem faced by children at home alone. One in three latchkey children the Longs talked to reported being frightened. Many had nightmares and were worried about their own safety. The most common way latchkey children deal with their fears is by hiding. They may hide in a shower stall, under a bed or in a closet. The second is TV. They often turn the volume up. It’s hard to get statistics on latchkey children, the Longs have learned. Most parents are slow to admit that they leave their children alone.

Question 48. The phrase “an empty house” in the passage mostly means

A. a house with no people inside

B. a house with nothing inside

C. a house with no furniture

D. a house with too much space

Cho hàm số y=f(x) có đạo hàm f ' ( x ) = ( x - 1 ) 2   ( x 2   - 2 x ) , với mọi x ∈ R . Có bao nhiêu giá trị nguyên dương của tham số m để hàm số y = f ( x 2   - 8 x + m )  có 5 điểm cực trị?

A. 16

B. 18

C. 17

D. 15

Mark the letter A, B, C, or D to show the underlined part that need correction in each of the following sentences.

(A) The novelist Shirley Hazzard is noted (B) for the insight, poetic style, and (C) sensitive she (D) demonstrates in her works.

A. The

B. for

C. sensitive

D. demonstrates

Tất cả các nguyên hàm của hàm số f(x)=cos2x là

A. sin2x+C

B. 1/2 sin2x+C

C. -1/2 sin 2x+ C

D. 2sin2x+ C