I. Multiple choice questions (*** 10 small questions, 3 points for each small question, out of 30 points)

1.(3 points) (20 14? Guangdong) If the square root is meaningful, the range of X is ()

A.

x> 1

B.

x≥ 1

C.

x< 1

D.

x≤ 1

2.(3 points) (20 14? Guangdong)

Among the following symbols, the one that can be regarded as a centrosymmetric figure is ().

?

A B C D

3.(3 points) (20 14? Guangdong) The math teacher assigned 10 to fill in the blanks, and got the following statistics after the exam:

Number of correct answers

seven

eight

nine

10

number of people

four

20

18

eight

According to the data in the table, the median and mode of the sample composed of correct questions in the class are (? )

A.8、8 B. 8、9 C.9、9？ D.9、8

4.(3 points) (20 14? Guangdong) The following functions: ①; ② ; ③ ; (4). When y decreases with the increase of x, the function is (? )

A. 1？ B.2？ C.3？ D. 4

5.(3 points) (20 14? Guangdong) The diameter of the cone bottom is 80cm, and the length of the bus is 90cm, so the central angle of its side development diagram is ().

A.320 B. 40 C. 160 D. 80

6.(3 points) (20 14? Guangdong) in the following four kinds of geometry, the top view is quadrilateral is ().

Answer? B C D

7.(3 points) (20 14? Guangdong) It is reported that in the first quarter of 20 13, the regional GDP of Guangdong Province was about1260 million yuan, which was expressed as () by scientific notation.

A.0.126×1012 yuan? B.1.26x1012 yuan C.1.26x1yuan? D.12.6×1011yuan

8.(3 points) (20 14? Guangdong) Real numbers A and B are known. If A > B, the following conclusion is correct ().

A.a﹣5