Do you hear my mother walking downstairs?为什么用walking不用walk?

Do you hear my mother walking downstairs?为什么用该walking不用walk? Do you hear my mother walking downstairs?为什么用walking不用walk? Do you hear my mother walking downstairs?为什么用该walking? walking dogs is not allowed 为什么用is 不用are? you shouldn't eat or drink while walking,为什么要用walking walking 用walk,to walk,walking,is walking填空：He ia too tired ( ). would you mind not walking( )my foot. but it within walking distance l will walk you I am too tired to (walk还是walking) 为什么? Walking is good exercise,为什么walk要加ing? The mother elephant isn’t _.A.walk B.walking C.to walk