Comets

基本解釋

Comets move around the sun like planets, but in long oval course.
彗星象行星一樣繞太陽(yáng)運(yùn)轉(zhuǎn)，然而其軌道呈狹長(zhǎng)的橢圓形。
That comet is invisible to the unaided eye.
那顆彗星衹用肉眼是看不到的。
We can see comets only when they come close to the earth.
衹有儅彗星接近地球時(shí),我們才能看得見(jiàn)它們。
A comet is at perihelion when it is closest (=very close) to the sun.
彗星最接近太陽(yáng)時(shí)，它就是在近日點(diǎn)。
If I had binoculars, I could see that comet clearly.
如果我有望遠(yuǎn)鏡，我就可以清楚地看見(jiàn)那顆彗星。