I haven't finished my homework because I was halping my mother all day yesterday.那个是主句?
问题描述：
I haven't finished my homework because I was halping my mother all day yesterday.那个是主句?
答
I haven't finished my homework 主句
because I was halping my mother all day yesterday.原因状语从句那如果改成hadn’t finished，后面用什么时态？这里不适合用过去完成时，因为all day yesterday 明确的过去的时间状语