问题 填空题

已知⊙O和⊙O'相切,它们的半径分别为3和4,则OO'=________。

答案

1或7

题目分析:相切包含两种情况:两圆外切或两圆内切.再进一步根据位置关系得到数量关系.

当两圆外切时,圆心距等于两圆半径之和,即

当两圆内切时,圆心距等于两圆半径之差,即

故答案为1或7.

点评:设两圆的半径分别为R和r,且,圆心距为d:外离,则;外切,则;相交,则;内切,则;内含,则

改错题

第三部分:写作(共两节,满分50分)

第一节:短文改错(共10小题,每小题1.5分,满分15分)

此题要求改正所给短文中的错误。对标有题号的每一行作出判断:如无错误,在该行右边横线上画一个勾(√);如有错误(每行只有一个错误),则按下列情况改正:

该行多一个词:把多余的词用斜线(\)划掉,在该行右边横线上写出该词,并也用斜线划掉;

该行缺一个词:在缺词处加一个漏字符号(∧),在该行右边横线上写出该加的词;

该行错一个词:在错的词下划一个横线,在该行右边横线上写出改正后的词。

注意:原行没有错的不要改。

My dear students, I didn’t know what I should say                              66._____________

to some of you who is still addicted to the Internet.                         67._____________

As teacher, I’d like to remind you that you’re                                 68._____________

wasting your time, energy, or even your life.                                          69._____________

You can never find the losing time and youth again.                         70._____________

As students, we should value the limited time to study                      71._____________

hard. As you know, you’ll graduate the school in two                       72._____________

months or so. After graduation, you won’t possibly                          73._____________

find out so good a condition to study in. So make full use of every    74._____________

minute to study hard so that you won’t feel sadly in the future.         75._____________

实验题