属纯黏液腺的小涎腺是（）
A.唇腺
B.颊腺
C.味腺
D.磨牙后腺
E.腭腺
参考答案：E
解析：属纯黏液腺的小涎腺是腭腺。
The book was written in 1946, ____ the education system has witnessed great changes. [ ]
A. when
B. during which
C. since then
D. since when
要使原料磨获得较高的产能，仓位分为（）为宜。
A、2
B、3
C、4
D、5
