—How about your travel?
—You can hardly imagine what difficulty we have had the vast desert.
A. explored
B. exploring
C. to explore
D. explore
网友回答
A. explored
(答案→)B. exploring
C. to explore
D. explore
解析：考查短语：have difficulty（in ）doing sth 做什么事情有困难.句意：你的旅行怎么样呀？你几乎不能想象出我们在探索大草原时有多么的困难。