题目内容
From far out in space, the Earth looks like a blue ball. Since water c1.three-fourths of the Earth’s surface, blue is the colour we see most. The Earth is shaped like a ball. It is 25,000 m2.around! It would take more than a year to walk around the whole planet. A s3.can fly around the widest part of the Earth in only 90 minutes.
Even though spacecraft have travelled to the Moon, people cannot visit the Moon without wearing special s4.. The Moon has no a5.or water. Plants and animals can’t live there either. American a6.first landed on the Moon in 1969. After that, there were more trips to the Moon. They brought back some Moon r7., which scientists are still studying.
The Sun is the closest star to our Earth. A star is a hot ball of burning gas. The Sun looks very big b8.it is so close. But in fact many of far-away stars are much b9.than our Sun. The burning gases from the Sun are so hot that they w10.the Earth from 93 million miles away!
