Ⅰ. 词汇
（A） 根据句意及首字母的提示，完成单词。
1. There are o_______ four hundred students in my school.
2. Our teacher told us that the earth is a p_______.
3. He like reading books, I a_______ like reading books.
4. If want to keep health, we must protect the e_______.
5. All the people can’t live without a_______. Because we have to breathe.
（B） 根据句意，用括号内所给单词的相应形式填空。
1. Scientists think that there has been life on Earth for _______(million) of years.
