若抛物线y2=2px(p>0)上三点的横坐标成等差数列,那么这三点与焦点F的距离

题型:选择题

问题:

若抛物线y2=2px(p>0)上三点的横坐标成等差数列,那么这三点与焦点F的距离的关系是 (    )

A.成等差数列

B.成等比数列

C.既成等差数列,又成等比数列

D.既不成等差数列,也不成等比数列

考点:抛物线的定义
题型:选择题

阅读理解。

     Many adults think that the decision to buy a computer is theirs. They are the world's webmasters.

But now, a US survey (调查) has found children are getting more and more interested in the Internet.

The number of children using the Internet has grown to three times in the past three years.

     Three years ago, the number of two to seventeen years old children entering the web world was

eight million. Today, the number has increased to 25 million. By the end of the year 2005, the number

of children on-line is expected to be 42 million.

     More and more children are using the net because their parents use it.

      The survey showed that the number of parents using the net has changed from 4.5 million and

16.4 million. The survey found many other interesting facts.

     Almost two-thirds of US families have home computers. Forty-six percent of all family members

are hooked (沉迷于) on the Internet.

      Girls are using the net as much as boys.

     In five years, schools will become the main gateways to the Internet for children.

1.By the end of year 2005, the number of children on-line will be _____ more than today.[ ]

A. 8 million

B. 17 million

C. 25 million

D. 42 million.

2. Why are more and more children using the net now? [ ]

A. Because they needn't go to school any more.

B. Because they will have exams on the net.

C. Because their parents often use the net and that affects (影响) them.

D. Because their teachers give lessons on the net all day.

3. What do you think of girls going on-line? [ ]

A. The girls go on-line less than boys.

B. They spend a lot of time on the net like boys.

C. They are weak in using the net.

D. The girls only use the net at school.

4.What may be the best title of the passage? [ ]

A. Adults Become the Owners of the Internet.

B. Children Lead the Internet.

C. How Do Children Use the Net?

D. The Growing Number of People Entering the Web World.

5. What are other interesting facts found by the survey?

(1) More and more children are interested in the Internet.

(2) Almost two-thirds of US family have home computers.

(3) Forty-six percent of all family members are hooked on the Internet.

(4) Boys use the net as much as girls.

(5) Schools will become the main gateways to the Internet for children in five years.[ ]

A. (1)(2)(3)(4)

B. (1)(2)(4)(5)

C. (2)(3)(4)(5)

D. (1)(3)(4)(5)

题型:选择题

这个标志是何含义?()

A.国道编号

B.省道编号

C.县道编号

D.乡道编号

题型:选择题

My money       . Could you please lend me some?

A.has run out of

B.was running out

C.has run out

D.was run out of

题型:选择题

8086/8088系统中,用于输入不可屏蔽中断的引脚是______。

A) INTR
B)


C) NMI
D) HOLD

题型:选择题

确定螺桨发动机地面工作时当量功率必须分别测量螺旋桨的()和().

A.力矩,反作用推力

B.轴功率,喷气推力

C.功率,转速

D.转速,正向推力

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