下列何种微生物会对细胞培养造成污染( )
A．军团菌B．支原体C．衣原体D．病毒E．螺旋体
参考答案：B
下列哪项不属于沉降性质药物的作用（）
A.泻下
B.清热
C.重镇安神
D.开窍
E.消导积滞
I was in the middle of my call because I had no money in my card.
A．called off
B．shut off
C．put off
D．cut off
