unit 4astronomy: the science of the stars
section awarming up & reading
题组ⅰ
ⅰ. 单词拼写
1. in old times people had a _________（理论）that the world was flat.
2. they have almost spent as much as one _________（十亿）dollars on this project.
3. because of the _________（猛烈的）natural disaster, a lot of people have lost their lives.
4. the other day he began a trip circling around the _________（地球）in an airplane.
5. even though the country is very ric
