Interrupting politely
You need to ask your boss a question. He is at his desk and looks really busy. It is urgent, what are three phrases you can use to interrupt him while still being professional and polite?

I'm (really) sorry to interrupt but ...
Sorry/Excuse me, can I just interrupt for a minute? 
Sorry, I know you're busy but I just have something quick to run by you.

Knock on the door, or knock on the panel of his cubicle, the say

"I am sorry to interrupt.  There is an urgent matter I need to bring to your attention."

Haha, Amanda works at a much less formal office.