易混淆的单词： COMETS

Scientists want to learn how comets come into being .

科学家们想了解彗星是怎么形成的。

Comets are big , dirty snowballs that orbit our sun .

彗星就像是围绕太阳转的巨大的，脏兮兮的雪球。

Researchers believe other comets are chemically similar to halley 's comet .

研究人员相信，其它的彗星在化学组成上与哈雷彗星相似。

Asteroids moons and comets have all been added to the stamp album .

小行星、行星卫星以及彗星已经全部增添到我们的集邮册上。

Several of the asteroids and comets that approach the earth-moon system will have been mined .

而一些靠近地球和月球的小行星和彗星将成为宝贵的矿藏。