问题 选择题
函数f(x)=log2x在区间[a,2a]上的最大值是最小值的2倍,则a等于(  )
A.
1
2
B.
2
2
C.
2
D.2
答案

∵2>1,

∴f(x)=log2x是增函数.

∴2log2a=log22a.

∴loga2=1.

∴a=2.

故选D.

阅读理解

阅读理解。

     What will the future be like?  It's possible that we may often  fly up into  space! Out  of all the coolest

inventions of the year, Times chose Spaceship One as the best.

     Spaceship One is a 6-meter-long white spaceship. On June 21st, American pilot Mike Melvill flew it

to space and  back-about 100 kilometers  up  into  the sky.  ①Some might say it's not a big deal.  You

know, people went to the moon years ago.

     Well, Spaceship One  is  special  because it is the first spaceship that wasn't made by the government.

A private(私人的) US company built and launched it. Lots of people want to travel in space. But it's too

expensive. American millionaire(大富豪) Dennis Tito  paid almost US $ 20  million  to  become the first

space tourist to visit the International Station in 2001. So private companies began to  think  of  making

their own spaceship to take other tourists up into space. The success of Spaceship One is a good start.

In the next 10 to 15 years, ②if you pay $20,000 to $100,000 you could fly high above the earth.

     ③What about having your own spaceship in your garage(车库)  and  taking  it  to  space  at  the

weekend?

1.将①处画线部分的句子翻译成汉语:

____________________________________________________________________________

2.将②处画线部分的句子改为同义句:

____________________________________________________________________________

3.将③处画线部分的句子改为同义句:

____________________________________________________________________________

4.Imagine(想象) what the future will be like.

____________________________________________________________________________

5.Do you want to have your own spaceship in your garage? Why?

____________________________________________________________________________

单项选择题