not until not before
5个回答

不可以用before,但是原因并不是他们说的那样.

如果用before的话句子应该是这样:i had knew nothing about the accident before my friend told me yesterday.

你能懂吗?

就是说主句的时间应该在被告诉时间之前,因此时态上应该再往前推一个