问题 选择题

注意到汽车车上设有安全带未系提示系统么?当乘客坐在座椅上时, 座椅下的开关S1闭合,若未系安全带(安全带控制开关S2断开)仪表盘上的指示灯L将亮起,再系上安全带时,安全带控制开关S2闭合,指示灯L熄灭。如图电路图设计最合理的是:

答案

答案:B

题目分析:C中S1与指示灯串联,跟S2并联,当乘客坐在座椅上时,指示灯亮,当系上安全带时,指示灯也亮,不符合题意,D中,S1与S2并联,当乘客坐在座椅上,不管是否系上安全带时,指示灯都亮,不符合题意。A中也是如此选项A不符合题意。而B中S1与指示灯串联,跟S2并联,当乘客坐在座椅上时,指示灯亮,但当系上安全带时,指示灯被短路而熄灭,符合题意,故只有B正确。

解答题
阅读理解

D

The Internet has become part of teenage life.

A new report on 3,375 students aged from 10 to 18 in seven Chinese cities found that 38 percent of them believe they use the Internet often.

While most of them get useful information and use the Internet to help in their studies, some are not using it in a good way.

In order to help young people use the Internet in a good way, a textbook on good Internet behaviour (行为) has started to be used in some Shanghai middle schools this term. The book uses real examples to teach students all about good ways of using the Internet. The book gives useful advice such as it’s good to read news or find helpful information to study.

Some students also make online friends. But if you are meeting a friend offline, make sure your parents know. Teachers and parents all think the book is of great help. A teacher said the book would be a guide for teens using the Internet. She believes it will keep students away from bad sites. “Many students are using the Internet without guidance from their parents,” she said. “The book will teach students how to be a good person in the online world.”

68. The textbook mainly tells us ______.

A. why we should use the Internet    B. how to study using the Internet

C. how to use the Internet correctly   D. how to get help from others

69. What’s the attitude of teachers and parents towards the textbook?

A. They are against it.               B. They are for it.

C. They don’t care about it.          D. The passage doesn’t mention.

70. According to the passage, teenagers are NOT encouraged to ______.

A. read online news          B. go online 

C. find helpful information online

D. meet a friend offline without letting their parents know

71. From this passage we know that _______.

A. more and more students have given up visiting bad Web sites

B. schools and teachers begin to pay attention to students’use of the Internet

C. no more homework will be given in Shanghai middle schools

D. less and less information can be found on line