板在安装前，先在墙或梁上铺设厚度不小于（）的水泥砂浆，称为坐浆。
A、5mm
B、10mm
C、15mm
D、20mm
参考答案：B
Miss Green didn't tell us _______ before she came to our school. [ ]
A. where does she live
B. where she lived
C. where she lives
D. which she lives in
治疗孕妇生殖道感染首选（）。
A.红霉素
B.多西四环
C.青霉素
D.氧氟沙星
E.阿莫西林
