It was Mr. Zhang that helped us out of the trouble. Without his help, we ______ it so easily.

A．can’t manage

B．mustn’t have managed

C．couldn’t have managed

D．couldn’t manage

中度苯中毒不会出现的症状是（）。

A.皮下可出现淤血、紫斑

B.肝脏肿大

C.抵抗力下降

D.血小板减少