What do you want to happen? If there is just one really really long word then it can't really break onto a different line, you just have to hide it.
On my site I have the CSS overflow:hidden set on the classes .qa-q-view-main and .qa-a-item-main - you could instead use overflow:auto if you want, which adds scrollbars if the content is too long.
EDIT: here on Q2A it looks like overflow:hidden is set on .qa-main
testtttttttttttttttttttttttttttttttttttttttttttttttttmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm