白喉棒状杆菌致病的最主要物质是（）
A.内毒素
B.外毒素
C.菌毛
D.侵袭性酶
E.β-棒状杆菌噬菌体
参考答案：B
— Do you think their table tennis team will win the first place at the coming sports meeting?
— ______. Ours is much stronger than theirs.
A．Of course
B．It depends
C．Don’t mention it
D．By no means
2，5，9，34，115，（）。
A．1271
B．1237
C．3910
D．13259
