The taecher is angry because some children ____(not finish) their homework.

问题描述:

The taecher is angry because some children ____(not finish) their homework.
答案是haven't finished,请问didn't finished为什么不行呢?

老师生气了,因为有人没有完成作业.
显然这是表示一个“结果”,产生了影响.所以完成时好.