Kate promised __ her little sister.A.her mother to look after B.to her mother looking after

问题描述:

Kate promised __ her little sister.A.her mother to look after B.to her mother looking after
C.to her mother to look after
D.her mother to looking after

A,能说下为什么吗这是固定搭配啊,promise sb to do一般除了make,let,have三个使役动词,其他及物动词都是加to do的