What does the original Hebrew say about Genesis chapter 6, where in the Christian bible, angels came down from heaven and had children with man? Does the Torah say that this happened, and that it was angels?
Jews don't always understand the simple meaning of any given verse of Torah - it always comes with thousands of years of commentary and tradition. The simple meaning of that sentence is unclear (the word "E-lohim" can mean "powerful ones," "angels" or "G-d"; "bnei E-lohim" means "sons of ...").
There's a debate about what exactly that word means in that case, but most commentators (Rashi, Ramban, Ibn Ezra) agree that it refers to "sons of judges" or the like. See http://www.sefaria.org/Genesis.6.2 for several commentaries to that effect.