根据句意和所给中文写出句中所缺的单词。
1. First, please_____________(介绍) yourself to us all, OK?
2. Something should be done to protect the _________(环境) in our hometown.
3. After________(检查) the computer, he told me there were no tickets.
4. Smoking will__________(当然) do harm to your health.
5. There will be an exciting football match between China and Japan on ________(频道) 5 tonight.