用括号内所给单词的适当形式填空。
1. There is a cup of ________(boil) water on the table.
2. Tea,the most popular drink is an ________(accident) invention.
3. The ________(nation) park lies in the mountain.
4. Can you name some ancient ________(ruler)?
5. When you enter the paper factory,the gas ________(smell) too terrible.
1.boiled 2.accidental 3.national 4.rulers 5.smells