设数列{an}的前n项和为Sn，且Sn=2-(12)n-1，n∈N．（Ⅰ）求数列

急速进入4000m以上高原后数小时至数天内出现意识丧失对于诊断高原脑水肿最有价值。()

阅读理解。

    It might help to understand a little about the nature of worry and what it is. With

worrying, the important thing is to understand if you can take action (采取行动) that will

reduce (减少) your worry and help you avoid whatever you're worrying about. For example,

you might want to study for the test next time! It's a case (情况) that a little worry can

be helpful. You're worried about the test, so you get down to (着手于) your studies.

    About a quarter of the kids say they turn to the Internet when they are worried. That

can be helpful in some cases-like when you're on this website, we hope! You might want to

use it as a starting point and then talk to someone about what you learned on the Internet.

But the Internet may not be enough for some worries.

    Only 9% say they try to do something about what is causing their worries, and about 25%

of kids keep their worries to themselves. Kids don't have to tell everyone everything, but

if they have serious worries, it's usually best to turn to someone who can help. Parents

and friends are the top choices, but some kids say they talk to teachers (13%) or doctors

and nurses (4%).

    Sometimes worry gets to be too much. It can make small problems seem bigger than they

are. And if the problem is actually a big one, just worrying about it probably won't help.

Worry can even hurt your sleep and keep you from having fun and doing your best. But we

don't wish you to worry about worrying!

1. Worry might be useful when _____. [ ]

A. it can help you sleep longer than ever

B. it can make you work harder at your lessons

C. it can make you more pleased

D. it can help you get in touch with your teacher

2. Where can you probably read this passage? [ ]

A. In a newspaper

B. In a book

C. On the Internet

D. In a magazine 21

3. Which of the following is TRUE according to this passage? [ ]

A. It is right to find out the reason why you are worried

B. Most students talk to their teachers when they are worried

C. Internet is always helpful every time you are worried

D. Worry can make big problems smaller than they are

4. What can be the best title for this passage? [ ]

A. Sometimes worry is helpful to you

B. Do something with your worry

C. Many children are seriously worried

D. Worry about worrying

谈谈对混合语的认识。

下列地域中，纯粹属于英美法系的有（）。

A.新加坡

B.南非

C.菲律宾

D.日本

纳税人被工商行政部门管理机关吊销营业执照的，应自营业执照被吊销之日起30日内，向原税务机关申报办理注销税务登记。（　　）