题目内容
We have always been interested in the Moon. 2000 years ago people already knew it
m1.around the Earth and where it would be in the sky at different times of the year. At that time, everything about the Moon was learned by watching it c2.in the sky.
When scientists could use telescopes to study the Moon more closely, their ideas began to change. They could see the Moon was made of r3.. Most scientists thought Moon rocks would be different from those on the Earth. This was because they believed the Moon had once been a planet that had been caught in the Earth’s g4.millions of years earlier.
In 1969 Moon rocks were finally brought to the Earth and s5.. Much to their surprise, scientists found that, except for water, the Moon and the Earth were made of the s6.things. Once again new ideas were needed for this new information.
After years of study, most scientists now think t7.the Moon was once part of the Earth. They believe very early in its history, maybe 4 billion (十亿) years ago, something about the size of Mars h8.the Earth. This sent billions of rocks into space around our
p9.. These rocks slowly joined together and after many years became the Moon.
In the future, even though our ideas about the Moon may change again, we will still be i10.in it.
