脑膜炎双球菌最主要的致病因素是（）
A.荚膜
B.外膜蛋白
C.内毒素
D.脂多糖
E.菌毛
参考答案：C
There is _____ pollution in the world. We must stop it. [ ]
A. much too
B. too much
C. many too
D. too many
配有纵向和环向缠结预应力的钢筋混凝土管叫自应力钢筋管。
