Umbrella is used _____ keeping yourself from rain.[ ]
A. from
B. to
C. for
D. as
答案:C
两条直线如果永远不相交,它们一定平行.______.
诊断支原体肺炎的主要依据是()
A.红霉素试验性治疗
B.痰细菌培养阴性
C.血清冷凝集试验阳性
D.临床表现
E.X线特异表现