可以用来鉴别烧碱和纯碱的是 [ ]
A. 醋酸
B. 紫色石蕊
C. 无色酚酞
D. 氯化钡溶液
AD
—We are going to have a football match this afternoon.
—_____.[ ]
A. Good luck!
B. Never mind!
C. Yes, please.
D. It's nothing.
弯管式质量流量计安装时,如果测量液体则传感器应()
A.朝上
B.朝前
C.朝后
D.朝下