Unit 4 Astronomy: the science of the stars
Ⅰ.单词拼写
1．What do you think of the new ________ (制度)?
2．“What happened？” John's mother asked him in a ________ (温和的) voice.
3．Before the Earth's protective ________ (大气层) was formed, there was no life except in the sea.
4．With the ________ (引力) of the moon and the sun each day, tides (潮汐) roll in and roll away.
5．He managed to finish the race, ________ (不像) more than half of the competitors.
6．His face wore a ________ (困惑的，迷惑的) expression.
7．Eating too many desserts can be ________ (有害的) to one's teeth.
8．The plane ________ (坠毁，碰撞) into the mountain.
9．According to the ________ (理论) of relativity (相对论), nothing can travel faster than
