问题补充：
---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
答案：
A. could have gone through
(答案→)B. must have gone through
C. might go through
D. need go through
解析：句意：你知道这个残疾人是如何成功地运营这么一个大公司的吗？我不知道，但是我想，他肯定经历了许多困难。问句中succeeded用的是过去时，可知答句中应该是对过去情况的推测。A、B两个选项都可表示对过去情况的推测，但A选项的语气很弱，意为：也许经历了不少困难吧。而根据问句中所说的残疾人成功运营大公司，应该推断他肯定经历了不少困难。故选B。
