He finished his homework yesterday afternoon (改为否定句)

问题描述:

He finished his homework yesterday afternoon (改为否定句)

He didn't finish his homework yesterday afternoon.他昨天下午没有完成作业.(didn't 后必须动词原形)
He hadn't finished his homework until yesterday afternoon.这样的意思就是:他直到昨天下午才完成作业.(这样成了原句的近义句了)