锌及锌合金不像黑色金属那样耐碱的侵蚀，所以不能采用强碱配制的清洗剂清洗。( )
参考答案：对
I’d like to go to Tommy’s birthday party this evening, but I _____ just _____ from the flu.
A．am---recovering
B．will--- recover
C．was--- recovering
D．had --- recovered
为使mA表稳定指示毫安值，曝光时间应大于（）
A.0.1s
B.0.2s
C.0.3s
D.0.4s
E.0.5s
