中国医药输入朝鲜大约在（）
A.晋
B.南北朝
C.隋唐
D.宋
参考答案：B
In England it is polite to _____. [ ]
A. point at somebody
B. eat half of the food
C. leave something in the bottle
D. finish eating something
孔径小于0.5μm的孔隙称为（）。
A.溶蚀孔隙
B.微孔隙
C.粒间孔隙
D.微裂缝
