Stephen Hawking，one of the world's most important scientists，believes that to go on living，humans must move into space， "Once we spread out into space， （A） our future should be safe，" he says.Today India，China，Russia and Japan are all planning to send astronauts to Earth's closest neighbor：the moon.It's "only" around 380，000 kilometers from us.Some of these countries want to create space stations there between 2020 and 2030.These stations will send humans to visit and later live on Mars or other Earth-like planets.
    However，not everyone thinks sending humans into space is a smart idea.Many say it's too expensive.And also most space trips are not short.For example，a one-way trip to Mars will need six months and another six months to come back.People travelling this kind of distance will face many health problems.What's more difficult than getting there is living there.For example，people who want to live on Mars will have to find water.Humans need water to live，and they would probably have to take （C） it with them from Earth.Finally，these first people would find life very difficult out in space.On the moon，for example，the sun's rays are very dangerous.People would have to stay inside the rockets most of the time.


（1）对号入座。①

C

C

②

D

D

③

A

A

④

B

B

①astronaut A.a flying machine used to travel to space
②Mars B.the way between two places
③rocket C.a person who travels into space
④distance D.a planet fourth in order from the sun
（2）写（A）处和（C）处划线单词所指代的内容． （A） our

humans'

humans'

（C） it

water

water

（3）列举人类不适合去太空的三个理由。（从选项中选出两个，将字母代号写在横线上。）
①

D

D

②

A

A

③

C

C

A.People travelling this kind of distance will face many health problems.
B.People would have to stay inside the rockets most of the time.
C.Life very difficult out in space.
D.It's too expensive.
（4）How long will it take to get to Mars and come back from Mars together？

Twelve months.

Twelve months.