If you do something on the off chance, you do it even though you think that there is only a small possibility of it being successful.
e.g. She takes a look at the forum on the off chance of meeting someone she knows. :)
"only too" means very.
e.g. We are only too pleased to help. :D
" over to you " is used to say that it's somebody's turn to do something.
- For Teachers