S700K转辙机上层检测杆用于()的工作状态。
参考答案:监督缩进密贴的尖轨
Jack doesn’t look ___ his father, but he walks ___ his father does.
A.as; as
B.as; like
C.like; likes
D.like; as
管道安装前应具备哪些条件?