---Do you know how this disabled man succeeded in running such a big company?

--- I don’t know , but I think he __________ many difficulties.

A．could have gone through

B．must have gone through

C．might go through

D．need go through

药用部位为根茎，含多种皂苷的药材是（）

A.天南星

B.莪术

C.石菖蒲

D.川贝母

E.知母