I didn’t know it could do terrible ______to your heart and lungs or ______was more difficult for smoking couples to become pregnant.

A．ruins; that

B．damage; it

C．damage; that it

D．sufferings; that this

细菌毒素中，毒性最强的是（）

A.破伤风痉挛毒素

B.霍乱肠毒素

C.白喉外毒素

D.肉毒毒素

E.金黄色葡萄球菌肠毒素