掘进工作面和顺槽刮板输送机，应沿机安设有发出停止或开动的信号装置，信号点设置间距不超过（）m。
A、10
B、12
C、15
D、18
参考答案：B
为什么小儿腹泻易发生脱水（）
A.肠液分泌过多
B.消化酶分泌较多
C.机体抵抗力弱
D.血中IgM较高
E.水代谢旺盛
What’s the speaker going to do with the letter
A．He would throw it away.
B．He would keep it.
C．He would post it.
D．He would stick a stamp on it.
