I read the book yesterday.(把句子中的时间状语改为before)

问题描述:

I read the book yesterday.(把句子中的时间状语改为before)

I have read the book before.

I have read the book before.(我以前就读过这本书)
before 可以单独用来作时间状态,就是指在说这句话以前,常用现在完成时。
有问题还可以再问我!

I have read the book before
我以前看过这本书

I read the book before today.