朱砂的粉碎常用()
A.串油
B.低温粉碎
C.水飞
D.蒸罐
E.超微粉碎
参考答案:C
Experiments of this kind ________ in both the U. S. and Europe well before the Second World War.[ ]
A. have conducted
B. have been conducted
C. had conducted
D. had been conducted
()就是指要有棱角,呈长条状的石料。
A.皱
B.瘦
C.漏
D.透