片剂肠溶衣材料可选用（） A.羟丙基甲基纤维素 B.丙烯酸树脂Ⅱ号和Ⅲ号混合液 C.

（）在“百花”时期率先质疑“社会主义现实主义”，发表著名论文《》。

－ Miss Jones once _____ music at Bardon School for ten years and now is an actress.

－ No wonder I often hear her sing in the garden. [ ]

A. had taught

B. taught

C. is teaching

D. has been teaching

 No sooner _____ themselves in their seats in the theatre _______ the curtain went up.

A．they have settled; before

B．had they settled; than

C．have they settled; when

D．they had settled;than

外用蚀疮去腐、内服截疟平喘的药是（）

A．升药

B．轻粉

C．砒石

D．铅丹

E．炉甘石

对液压油的特殊要求是（）

A.良好的抗氧化安定性

B.良好的抗磨性

C.不得含有产生气体的杂质

D.凝点要低