Greg Clarke

Request: Your boss asks you to supervise this season's intern last
seen with her feet up on a desk, iPod on, Gameboy in hand.
What you should say: "Wow, that's an interesting project. I'm
really busy with the ABC assignment right now, so let me know if
you want me to re-prioritize."
Why it works: "Asking your boss to prioritize tasks for you means
you don't have to actually say the no word," author Patti Breitman says. If she
tells you to just squeeze the new task in, then do it. But keep a
list of all the extra work you've done for your next review.
Why you shouldn't feel guilty: You really do have enough work to do
as it is.
How to avoid the situation in the future: If extra tasks keep
getting dumped on your desk, ask your boss for a meeting. Explain
that the added assignments are making it hard to do your primary
job properly. Ask if she wants to review your job description (and
renegotiate your salary while she's at it).