黄头病毒颗粒呈杆状,有囊膜,上有纤突样突起,病毒核酸为()
A.单链RNA
B.双链RNA
C.线状双链DNA
D.环状双链DNA
参考答案:A
He smokes in the bus. I think he has no _____ at all. [ ]
A. habits
B. customs
C. polite
D. manners
下面哪些不属于组网拓扑切换?()
A.频内切换,
B.基于覆盖的切换,
C.频间切换,
D.基站内切换.