I wondered what great difficulty he had the plan.
A. to carry out
B. carrying out
C. carried out
D. with carrying out
网友回答
A. to carry out
(答案→)B. carrying out
C. carried out
D. with carrying out
解析：句意：我想知道他实施这个计划有多难。这句话用了have difficulty（ in）doing这个词组，意思是“做…很困难”，这里因为是感叹句所以把what great difficulty放在了前面，选B。