工件残余应力是指在没有外力作用的情况下,存在于工件内部的应()。
A、引力
B、重力
C、惯性力
D、力
参考答案:D
A.光也是一种电磁波
B.电磁波能在真空中传播
C.根据c=λf可知,频率越高的电磁波波长就越短
D.根据c=λf可知,频率越高的电磁波波速就越大
小题1:My father works as a _______ (卫兵) to keep our city safe.
小题2:What _______(其它的) do you like to do besides playing basketball?
小题3:The students held a party and _______ (庆祝) the birthday for her.
小题4:I need to eat less meat because my w_______ is over 80 kilograms.
小题5:The actress m_______ to a rich man last year.
小题6:The a_______ age of the students in our class is 13.
小题7:We agree with you, but our parents maybe d_______.
小题8:The teacher gave us an _______ (instruct) to us about how to use the machine.
小题9:As the _______ (city) of Guangzhou, we’re responsible for keeping the city clean.
小题10:Please hand in your homework on time, or you will _______ (punish).