Which of the following molecules or ions does not contain lone pair(s)? ()

一般情况下，车刀工作角度与刃磨角度变化不大，加工中基本不用考虑其影响。

判断题一般情况下，车刀工作角度与刃磨角度变化不大，加工中基本不用考虑其影响。

绕线式三相异步电动机串电阻可实现平滑调速。

判断题绕线式三相异步电动机串电阻可实现平滑调速。

She had been at the company for 10 years and knew all t...

单项选择题She had been at the company for 10 years and knew all the ___. A.
ins and outs B.
up and down C.
on and off D.
 back and forth