片剂包薄膜衣时作为掩蔽剂使用的是（）
A.羟丙甲基纤维素
B.乙醇
C.丙二醇
D.二氧化钛
E.色素
参考答案：D
The factory was built in a secret place, around _________ high mountains.
A．which was
B．it was
C．which were
D．them were
饲料在消化道内的分解过程称为（）。
A、溶解
B、吸收
C、软化
D、消化
