题目内容：

Extract（摘要）1 

A computer is an "information processor".It is given information,called "data",instructed to do certain things and then show us the results.The data put into the computer is called the"input" and the results which come out are the "output".Some people say the circle of large standing stones at Stonechenge is a kind of computer.Prehistory people worked out their calendar（日历）from the position of the shadows made by the sun shining on the stones. 

Extract 2 

Teach yourself new subjects and skills at your own pace with a home computer.Use it to help with schoolwork,for self-improvement,even to improve your career skills.Learn touchtyping.  Foreign languages or computer programming.A home computer can help children of all ages learn classroom subjects such as spelling,geography and others.In fact it makes learning fun.So if you want to teach yourself,or help your children teach themselves-get a home computer.It can also help you manage your personal finances or help you to work taxes and plan household budgets.You can make business a pleasure with a home computer. 

1.The writer introduces the words such as "input" and "output" in order to_____. 

A．introduce people to computer language

B．show computer language is the same as English

C．help people some scientific language

D．give people some scientific language

2.Why does the writer talk about Stonechenge in Extract 1?

A．To give an example of the very first computer.

B．To show that computers are older than mankind.

C．To tell the difference between the past and the present.

D．To give another way of explaining computers.

3.If you think of the circle of large standing stones as a computer,_____. 

A．the shadow is the input and the position is the output

B．the sunlight is the input and the calendar is the output

C．the position is the input and the sunlight is the output

D．the calendar is the input and the shadow is the output

4.Extract 2 is probably taken from_____.

A．a computer textbook	B．a company's advertisement
C．a teach-yourself computer book	D．a children's guide to computers