Comets

常见例句

Comets move around the sun like planets, but in long oval course.
彗星象行星一样绕太阳运转，然而其轨道呈狭长的椭圆形。
That comet is invisible to the unaided eye.
那颗彗星只用肉眼是看不到的。
We can see comets only when they come close to the earth.
只有当彗星接近地球时,我们才能看得见它们。
A comet is at perihelion when it is closest (=very close) to the sun.
彗星最接近太阳时，它就是在近日点。
If I had binoculars, I could see that comet clearly.
如果我有望远镜，我就可以清楚地看见那颗彗星。
The comet's ice, heated by the sun, rapidly and spectacular sublimate to gas.
彗星上的冰块在太阳热的作用下迅速而壮观地升华成气体。