限位器的作用是什么？
参考答案：
是限制机构运行时通行范围的。一是保证起升机构安全运行的上升极限位置和下降极限位置，二是限制运行机构的运行极限。
Wouldn’t you feel rather________if you rushed to the airport to meet your friends only to find that they
had already been picked up by other people?[ ]
A. satisfied
B. happy
C. annoyed
D. bored
车行道通行能力
