被灭活的病毒不能保留的特性是()
A.抗原性
B.红细胞吸附性
C.感染性
D.血凝性
E.细胞融合
参考答案:C
-Where is Tom?
-He hasn't come to school today. I think he __________ be ill.[ ]
A. has to
B. should
C. may
D. need
能使动脉血压波幅增大的原因是
A.心动过速
B.小动脉硬化
C.主动脉瓣狭窄
D.大动脉硬化