space travel,have been to,work hard,a group of,by spaceship
—Not yet!It will be done in a few minutes.
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一Yes, I them twenty minutes ago.
What wilI our life be like by the year 2100? It's difficult for us(imagine).People (live)on the earth for so many years.It is becoming more and more crowded and polluted.Maybe people will live on the other planet--Mars.Astronauts (not be)to Mars yet so far.Let's imagine what our life will be like on Mars.I think life on Mars will be better than(those)on the earth in many ways.People will have more space.Robots will do most of work.so people will have more time for(hobby).What's more,there will be no school on Mars.Every student will have a computer at home.They can study,do their homework and take exams online.