Mary is a good girl .She is good

问题描述:

Mary is a good girl .She is good
Mary is a good girl .She is good at()the house.
A.cleans
B.clean
C.clraning

CWhythisisC?ldon'tknowhiare you here?can you tell me?at是介词
介词后的动词都必须加ingCanyoutell meenglish