问题 填空题

在四边形中,若有一组对角都为90°,另一组对角不相等的四边形我们称它为“垂直”四边形,那么下列说法正确的序号是       . (多填或错填得0分,少填酌情给分).

① “垂直”四边形对角互补;     ②“垂直”四边形对角线互相垂直;

③“垂直”四边形不可能成为梯形;④ 以“垂直”四边形的非直角顶点为端点的线段若平分这组对角,那么该“垂直”四边形有两组邻边相等.

答案

①③④

分析:根据四边形的内角和为360°,可得到①③正确;由于没有给定对角线的限制条件,不能得到②“垂直”四边形对角线互相垂直;利用三角形全等可以判断④正确.

解:根据四边形的内角和为360°,可得“垂直”四边形对角互补,所以①正确;

垂直”四边形对角线不一定互相垂直,②不正确;

因为“垂直”四边形有一组对角都为90°,另一组对角不相等的四边形,根据四边形的内角和为360°可得不能有相邻的角都为90°,则“垂直”四边形不可能成为梯形,所以③正确;

以“垂直”四边形的非直角顶点为端点的线段若平分这组对角,则可以得到被这条线段分成的两个三角形全等,则该“垂直”四边形有两组邻边相等,所以④正确.

故答案为①③④.

多项选择题
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阅读理解

     People always think about "the problem of youth". If there is one-which I take leave to doubt-it is

older people who create it,not the young themselves.Let us get down to fundamentals and agree that the

young are after all human beings-people just like their elders.There is only one difference between an old

man and a young one:the young man has a beautiful future before him while the old man a splendid future

behind him and maybe that is where the rub is.

     When I was a teenager,I felt that I was just young and unknown-that I was a new boy in a huge

school,and I would have been very pleased to be regarded as something so interesting as a problem.For

one thing,being a problem gives you a certain identify,and that is one of the things the young are busily

engaged in seeking.

     I find young people exciting.They have an air of freedom,and they have not a dull promise to mean

ambitions or love of comfort.They are not anxious social climbers,and they have no devotion to important

things.All this seems to me to link them with life,and the origins of things.It's as if they were in some sense

of cosmic beings in violent and lovely contrast with us suburban (乡村的) creatures.All that is in my mind when I meet a young person.He may be too proud,illmannered,selfconfident or selfsatisfied,but I do not

turn for protection to boring clich?s about respect for elders as if age were a reason for respect.I accept

that we are equals,and I will argue with them,as an equal,if I think he is wrong.

1. "The problem of youth" in Paragraph 1 means the problem________.

A. caused by young people

B. needed to be solved by young people

C. young people meet

D. created by the old for the young

2. The underlined word "rub" is closest in meaning to________.

A. fact  

B. age

C. future  

D. difficulty

3. One of the things the young are engaged in is that they want to________.

A. climb up the social ladder

B. have freedom

C. be known

D. make troubles

4. By saying "anxious social climbers",the writer refers to________.

A. some mean adults  

B. ambitious young people

C. capable political leaders

D. people who pursue comfort