光年

guāng nián shì tiān wén xué li de jù lí dān wèi

光年是天文学里的距离单位。

Light year is a unit of distance in astronomy.

dì qiú lí zuì jìn de héng xīng dà yuē wéi guāng nián

地球离最近的恒星大约为5光年。

The nearest star to earth is about 5 light years away.

yī guāng nián jiù shì guāng yī nián suǒ zǒu de jù lí

一光年就是光一年所走的距离。

A light-year is the distance light travels in one year.