Do you hear my mother walking downstairs?为什么用该walking不用walk?hear sb do sth听见某人做过某事hear sb doing听见某人正在做某事这道题中应该是听见母亲下楼了,是做过了某事啊!

Do you hear my mother walking downstairs?为什么用该walking不用walk?hear sb do sth听见某人做过某事hear sb doing听见某人正在做某事这道题中应该是听见母亲下楼了,是做过了某事啊!
Do you hear my mother walking downstairs?为什么用该walking不用walk?
hear sb do sth听见某人做过某事
hear sb doing听见某人正在做某事
这道题中应该是听见母亲下楼了,是做过了某事啊!

Do you hear my mother walking downstairs?为什么用该walking不用walk?hear sb do sth听见某人做过某事hear sb doing听见某人正在做某事这道题中应该是听见母亲下楼了,是做过了某事啊!
意思是听见我妈妈正在下楼,不是下楼了,所以用ing