引风机排尘烟囱过低有什么危害？
参考答案：易造成地面大气污染，给人身体造成伤害。
--- Bob feels really sorry, Jean.
--- I wouldn’t accept his excuses unless he takes back what he said.
A．What for?
B．So what?
C．No doubt.
D．No wonder.
“净重”栏应填( )。
A．18.90
B．15025
C．17951
D．不填
