对洁净区的要求错误的是
A.建筑物表面能耐受多种清洁剂的清洗
B.不必要的物品不得带入
C.尽量减少人员出入
D.可以根据生产情况,安排三班生产
E.消毒和洁净剂应轮换使用
参考答案:D
You that late last night. It was harmful to your health. [ ]
A. mustn't have worked
B. shouldn't have worked
C. can't have worked
D. mightn't have worked
鉴别氢气、一氧化碳两种气体,下列说法正确的是( )
A.观察颜色
B.闻气味
C.点燃后看发出火焰焰色
D.检验燃烧的产物