Need to go out for a while, but can't resist relating a family gem...
Years ago, my niece, Maureen, was instructing her little boy, Joel, then 4,
how to do something, and he was frustrated.
"She gently told him, "Just try, Joel."
Probably looking something like this - - 
- -
he came up with a classic...
"But, Mommy - I CAN'T KNOW HOW TO TRY TO!!"
(we still find that useful it in certain situations..:)