Don’t be in a hurry. We are supposed this problem step by step.
A. solving
B. to solving
C. to solve
D. solve
网友回答
A. solving
B. to solving
(答案→)C. to solve
D. solve
解析：句意：别着急。我们应该一步步地解决这个问题。in a hurry着急；step by step逐步地；“应该做某事”是“be supposed to do sth.”，所以空格处应该用动词不定式，故选C。