根据句意及首字母提示写出所缺单词。
1. I am really a____ because I can't find my backpack.
2. I didn't c____ the early bus, so I had to wait for the next.
3. The s____ of the coffee is so good, and I want to drink one more cup.
4. —How many f____ do you have?
—I have ten.
5. Don't p____ to know what you don't know.
