梅毒
A.髂嵴下2横指B.髂嵴上2横指C.髂嵴水平D.胆囊区E.原来的位置
参考答案:D
计算题:燃烧75吨含碳酸钙80%的石灰石能制得多少生石灰?(相对原子质量:Ca=40,C=12,O=16)
— I think English is __________ unimportant subject.
— I don’t think so. It is __________ useful tool when we talk with foreigners.
A.a; an
B.an; a
C.a; a
D.an; an