I really appreciate to help me with my maths, but I’m afraid that I have no time this week．
A. you to offer
B. it you offer
C. your offering
D. this you are offering
网友回答
A. you to offer
B. it you offer
(答案→)C. your offering
D. this you are offering
解析：appreciate doing, your作动名词offering的逻辑主语。