直到我读了那本书,我才知道那件事是多么的容易,如何翻译

as far as I read the book,I know that is so easy.

Just after I read that book, I known how easy that thing was.

对补充：
好像用不上...没有这种说法。

I didn't realized how easy the book was until I read it.

I didn't think it was so easy until I read that book.

I didn't think it was so easy as far as I read that book.