It was long before I knew it.

过了很久我才知道那件事。

youdao

It was not long before I knew it.

我不久就知道了这件事。

youdao

I knew Mr Smith long before I knew you.

早在认识你之前我就认识史密斯先生了。

youdao

I knew him long before you do.

在你认识他之前很久我就认识他。

youdao

I knew him long before you do.

在你认识他之前很久我就认识他。

youdao