All the neighbors admire this family ______ the parents are treating their child like a friend.

A．why

B．where

C．which

D．that

把往复式压缩机的各个弹簧放在升程限制器的簧窝内，压缩至各圈贴合，此时弹簧应比簧窝边缘（）㎜。

A、高1~2

B、低1~2

C、高2~3

D、低3~5