about " excited about" "excited by" and " excited at". there are 3 sentences which are 1. I was very excited at the prospect of going to Europe. 2. I was very excited about becoming an uncle. 3. We're all excited by the prospect of a party. I'm wondering the rule of using "by","at""about" naturally and correctly. by the way, as you see the 1 and 3 have the very similar form, does they mean some differences by using "at" or "by". thank a lot for your opinion