适合下列条件的△ABC中，是直角三角形的个数为（　　）

①a=6，b=8，C=10；

②三边长满足a²-c²=b²；

③∠A=32°，∠B=58°；

④∠A：∠B：∠C=3：4：5．

A．1

B．2

C．3

D．4

V：短文改错（共10小题；每小题1分，满分10分）

此题要求改正所给短文中的十个错误。

1．把多余的词用斜线（\）划掉，在下面横线上写出该词，并也用斜线划掉。

2．在缺词处加上一个漏字符号（∧），在下面横线上写出该加的词。

3．在错的词下划一横线，在下面横线上写出改正后的词。

Recently I have learned from the internet that traffic accidents were happened frequently, which mainly resulted from drinking driving.

Many drivers think they are luckily to avoid accidents. As the matter of fact, no one could afford to risk their lives driving after drinking. Drunk driving will not only threaten the life of the drivers as well as other people, and also make their family suffer from anxiety caused by it. In addition, drunk driving against the law and more and more people are punished for them.

In a word, for the sake of the safety of all people, please not drive after drinking.