在直齿圆柱齿轮设计中,若中心距保持不变,而把模数增大,则可以()。
A、提高齿面接触强度
B、提高轮齿的弯曲强度
C、弯曲与接触强度均可提高
D、弯曲与接触强度均不变
参考答案:B
若一个梯形内接于圆,有如下四个结论:①它是等腰梯形;②它是直角梯形;③它的对角线互相垂直;④它的对角互补.请写出正确结论的序号.______(把你认为正确结论的序号都填上).
短文改错(共10小题;每小题1分,满分10分)
假定英语课上英语老师要求同桌之间互相修改作文,请你修改一下作文。文中有十处语言错误,每处最多有两处。错误涉及一个单词的增加、删除或修改。按下列情况改正:
删除:把多余的词用斜线(\)划掉。
增加:在缺词处加一个漏字符号(∧),并在该词下面写出该加的词。
修改:在错的词下划一横线,在该词下面写出改正后的词。
注意:1、每处错误及修改均仅限一词。
2、只允许修改10处,多者(从11处起)不计分。
It is reported, some needy students receive financial support from some kind people but never express our thanks. Personally, I think they are wrong. Though the helpers didn’t expect any reward in return, it is necessary and good manner to say “thank you”. Besides, it is a basic social skill express ourselves in modern society. Maybe some of them do feel thankfully. It is only because they are afraid of looked down upon which they remain silent. But I just want to say that being poor for a moment doesn’t means you will be poor forever.