2021年春季初三年 晋江二检 阅读理解

阅读理解（D）

Maybe some day our children will end up living in Mars ? Here some fascinating facts about Mars.

Mars is far less than half the size of the Earth .Though it's smaller,the surface area of Mars that you can stand on is equal to that of  the Earth,because the Earth is mostly covered  by water .The atmosphere on Mars is really thin--100 times thinner than on Earth ,and it's not breathable,for it's 96 percent CO2.It's really    cold there.The average temperature is minus 81 degrees,although there is quite aquite a range of temperature .A day on Mars is about as long as a day on Earth,plus about 39 minutes.Seasons and years on Mars are twice as long as they are on Earth .Mars has a lot less gravity than on Earth,and it's the kind of place where you can jump over your car instead of walking around it.

Now,as you can see,Mars isn't exactly Earth-like,but it's by far the most livable other place in our entiresolar system.

And here is what you need to live on Earth:food,water,shelter and clothing.And here's what you need to live on Mars :all of the above,plus oxygen .

Let's look at the most important thing on this list first.As we know,water is the basis of all life and it's far too heavy to carry water from the Earth to Mars,so we have to find water on Mars.Mars looks just like a desert.But actually it's not.The soil on Mars contains up to 60 percent water.And a number of orbiters flying around Mars have shown us that many craters on Mars have water ice in them.Orbiters also tell us that there are huge amounts of underground water on Mars as well as glacier . In fact,if only the water ice at the poles on Mars melted,most of the  planet would be under 30 feet of water.

Water comes first .Next we have to think about  the atmosphere.