肠道杆菌O抗原为()。
A.细胞壁脂多糖层
B.鞭毛蛋白
C.氨基糖聚合物
D.60℃,30分钟即被破坏
E.与细菌运动有关
参考答案:A
含0.5mol Na2SO4的溶液中,Na+ 约为( )个
A.0.5
B.1
C.3.01×1023
D.6.02×1023
Alex: Why are you still here? It’s almost eight o’clock. Tom: Because I my work.
Don’t worry. It’s almost done.
A.wasn’t finishing
B.wouldn’t finish
C.haven’t finished
D.won’t finish