下列物质属于纯净物的是（ ） A．医用酒精 B．生理盐水 C．生铁 D．硫酸

阅读理解。

    I am Catherine. I love rock very much. I mean I like climbing mountains not rock music. I like touching

the rock and reading the face of the rock. I like it a lot. I feel at home on the side of a mountain. Climbing is

only my hobby. I have two long holidays every year. I often climb mountains during the holidays. I am

different from other climbers. I often climb the mountains without ropes (绳子). I climb many mountains in

many countries but most often in the A mountains near D City, where I live.

    I started climbing near my home in Paris when I was five years old. I was good at climbing at that time.

I joined Climb Club to learn more when I was fourteen years old. I won my first competition in Italy in 1995.

    Three years ago I tried to find a new route (路线) up the b Mountain near D City. The climb took eleven

days and at last the snow was so heavy that I could not move. I'm going to try again this year.

1. Catherine didn't start climbing mountains until ______. [ ]

A. she was five

B. she joined the club

C. 1995

2. On the side of a mountain she always feels ______.

A. worried

B. happy

C. lucky

3. Catherine joined the Climb Club when she was ______ years old. [ ]

A. 5

B. 14

C. 16

4. She couldn't climb up the B Mountain, because ______. [ ]

A. Catherine lost her way

B. the climb took 11 days

C. it was too hard for her to move in the snow

5. Which of the following is true according to this passage? [ ]

A. Catherine won her first competition in France in 1995.

B. Most climbers climb the mountains without ropes.

C. Catherine lives somewhere near Chamonix.

基因控制蛋白质的合成过程包括 [ ]

A．复制和转录

B．复制和翻译

C．转录和翻译

D．复制和逆转录

每个时区所跨的经度是（  ）度，全球可划分为（  ）个时区。

A．7．5 12个

B．12 20个

C．24 24个

D．15 24个

根据科斯定理，可以通过市场机制解决外部性问题的前提是()。

A.交易成本为零或者很小 

B.财产权明确 

C.财产权明确切交易成本为零或者很小 

D.财产权明确切交易成本足够大 

( )不易长期使用。

A．一体化战略

B．密集型战略

C．稳定型战略

D．收缩型战略