— How about your travel? — You can hardl
问题:
— 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
— 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