简述缺氧对脑组织造成的损害。

阅读理解。

     When I was a girl of 10, I joined the school cross-country team and practiced twice a week, on the

1,8-km course I'd never really run before and I thought the course would be easy. It was a real shock I ran

out of breathe (喘气) within the first few minutes. I never realized how tiring running could be but I didn't

think about give up.   

     Over time, I did get a little bit faster. However, I was really slow. In races, I would finish close to last.

I'd always have to stop more than once, especially in the longer races, which were 2. 5 to 2. 8 km. After

every race, I'd go home and cry. But 1 still didn't stop running, holding onto that picture of crossing the

finishing line and finally doing well.

     Then one of my friends joined the team, too. She could run easily and even came in the 18th in a big race!

I felt so slow and my confidence (自信) was lower than ever. I became so nervous when I thought of the

races that I wanted to give up badly.

     Still. I refund to. Finally. I realized that the reason I was to nervous was that I was always worried that

I wasn't ready for them. So a few weeks before the next 2. 8-km race. I practiced running almost 3 km every

day. which helped me improve my pace (步伐).

     When the time came for the big race, all that practicing really paid off. I stopped only once and my pace

was so much better.

     I realized that I'd finally gotten happiness with running. But the funny thing was. It didn't come from

doing better, Instead, it came from the fact that I hid tried harder and never given up.

1. Before she took the 1.8-km course, the writer ________.

A. knew a lot about it

B. wanted to be a great runner

C. practiced running every day

D. never thought running so tired

2. The writer was nervous about the race because she _______.

A. had to stop to drink water

B. was worried she wasn't ready

C. run slower than anyone else

D. could find no coach to help her

3. The underlined phrase "paid off" probably mean "______".

A. brought good results

B. coat a lot

C. saved much time

D. came to fail

4. It can be inferred (推断) from the passage that the writer ______.

A. got angry with her friend

B. wasn't pleased with herself

C. was a person with a strong mind

D. had no Interest In running

（1）少壮不努力， 　　　　       。（《长歌行》）

（2）　 　　      ，波撼岳阳城。（孟浩然《望洞庭湖赠张丞相》）

（3）与独爱莲之出淤泥而不染， 　　　                。（周敦颐《爱莲说》）

（4）国破山河在，                           。（杜甫《春望》）

（5）                          ，烟波江上使人愁。（崔颢《黄鹤楼》）

（6）无丝竹之乱耳，                             。（刘禹锡《陋室铭》）

滑动轴承温度不超过（），滚动轴承温度不起过（）。

草原等级评定中，用（）表示草原草群品质的优劣。

A．等

B．级

C．类

D．度

接触燃烧式可燃气体报警仪的铂金丝外涂有（）。

A.氧化锆

B.氧化铝

C.氧化锌

D.氧化亚铁