通过（）可确认排烟风机已正常运行。
A.看电机是否转动
B.打开油箱孔，看是否有风吸入
C.看油箱的真空表指示
D.摸风机是否振动
参考答案：A, B
作血型鉴定时，红细胞用生理盐水配制的浓度一般应为（）
A.1%
B.2%
C.8%
D.10%
E.20%
--How many people were there at the meeting?
-- _______. All the people went on a trip to Beijing.
A．Nobody
B．No one
C．None
D．Nothing
