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问题 解答题

电信公司推出两种移动电话计费方法：计费方法A是每月收月租费10元，可免费通话100分钟，此外超出部分通话时间按0.3元/分钟加收通话费；计费方法B是不收月租费，通话时间按0.2元/分钟收通话费．

（1）某用户某月要拨打x分钟，分别求出两种方案的话费 （用含x的代数式表示）．

（2）请根据通话时间的多少，选择比较省钱的一种付费方式．

答案

（1）A方案：当0≤x≤100时，话费是10元，

当x＞100时，话费是10+0.3（x-100）=（0.3x-20）元．

B方案：话费是0.2x元．

（2）x＞100时：

0.3x-20＞0.2x，

解得：x＞200，

∴方式B省钱；

0.3x-20=0.2x，

x=200，

两种方式花费一样；

0.3x-20＜0.2x，

x＜200，

∴100＜x＜200时方式A省钱；

0＜x＜100时：

0.2x=10，

x=50，

当0＜x＜50时，方式B省钱，x=50时，两种花费一样多，50＜x≤100时，方式A省钱．

总之：当0＜x＜50时，方式B省钱，当x=50时，两种花费一样多，

当50＜x≤100时，方式A省钱，当x=200时，两种方式花费一样，当x＞200时，方式B省钱．

阅读理解

Perhaps you have heard a lot about the Internet, but what is it, do you know? The Internet is a network. It uses the telephone to join millions of computer together around the world.

Maybe that doesn’t sound very interesting. But when you are joined to the internet, there are lots and lots of things you can do. You can send e-mail to your friends, and they can get them in a few seconds. You can also do with all kinds of information on the World Wide Web (WWW).                                              

There are many different kinds of computers now. They all can be joined to the internet. Most of them are small machines sitting on people’s desks at home, but there are still many others in schools, offices, or large companies. These computers are owned by people and companies, but no one really owns the internet itself.

There are lots of places for you to go into the internet. For example, your school may have the internet. You use it during lessons or free time. Libraries often have computers joined to the internet. You are welcome to use it at any time.

Thanks to the internet, the world is becoming small. It is possible for you to work at home with a computer in front, getting and sending the information you need. You can buy or sell what ever you want by the internet. But do you know 98% of the information on the internet is in English? So what will English be like tomorrow?

小题1:What is the passage mainly about?

A internet     B information       C computers       D E-mails

小题2:Which is the quickest and cheapest way to send messages to your friends?

A by post     B by e-mail       C by telephone     D by satellite

小题3:Which may be the most possible place for people to work tomorrow?

A in the office     B at school     C at home    D in the company

小题4:Who is the owner of the internet?

A The headmaster    B The officer     C The user      D No one

小题5:What does the writer try to tell us with the last two sentences?

A English is important in using the internet.

B The internet is more and more popular.

C Most of the information is in English.

D Every computer must have the internet.
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单项选择题

空中交通服务电报中，表示取消重复与非重复性飞行预报的电报标志是（）。

A.CNL

B.ABS

C.CHG

D.ACP
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