流感病毒分型的依据是()
A.核蛋白
B.血凝素
C.神经氨酸酶
D.基质蛋白M1
E.核酸
参考答案:A
In the _____ of proof, the police could not take action against the man. [ ]
A. lack
B. shortage
C. absence
D. failure
多层砌体房屋在地震中常出现交叉型斜裂缝,其产生原因是下列哪一个
A.轴心受压承载力不足 B.抗主拉应力强度不足C.受弯承载力不足 D.偏心受压承载力不足