单选题 {{B}}B{{/B}}
When man began to search the skies, he saw a lot of things. In the universe(宇宙), the earth seemed to be just a small bit of dust. It is only a small planet, and travels around the sun. The sun together with its planets, travels in the Milky Way(银河), our galaxy(星系). The Milky Way has about thirty billion stars like our sun, and is one of about a hundred million galaxies in the universe.
Because the space (空间)is so great, it is difficult to work out how far away a star is. Instead of kilometres, we have light-years. A light-year means how far light travels in one year. Our nearest neighbour galaxy is more than 9000,000 light-years away from the earth.
单选题 Man has known that ______ .
【正确答案】 D
【答案解析】本题的关联句是文章开头的第二句：在宇宙中地球就像一点灰尘一样，只有D项对地球作了描述，其余三项是对太阳、银河星系的叙述，不合题意。
单选题 A galaxy is the name of ______ .
【正确答案】 A
【答案解析】本题是对星系(galaxy)的解释，星系是由很多恒星组成。但星系不等于宇宙，也不仅指像地球一样的行星，更不仅指太阳，故B、C、D均错误。
单选题 In the Milky Way we can see many ______ .
【正确答案】 D
【答案解析】根据文中所述，银河系有无数个像太阳一样的恒星，据此，B、C意思相同，故选D。
单选题 We use ______ to work out how far a star is from us.
【正确答案】 C
【答案解析】计算宇宙中天体之间的距离，用光年。