内毒素的毒性分子是（）
A.脂蛋白
B.核心多糖
C.类脂A
D.特异多糖
E.磷脂
参考答案：C
Do you still remember the key points that ___________ in his report? I don’t remember them all.
A．referred to
B．were referred
C．he was referred to
D．were referred to
直流控制熔断器（即保险）的操作有何规定？
