最佳答案:

　　1、Neil Armstrong took his first flight at the age of six.

　　2、Yuri Gagarin became the first man to go into outer space when he was 27.

　　3、People might move to another planet in the future because of the rapid increase in the population on the Earth.

　　4、Without fresh food,meals will not be as tasty as they are today.

　　5、It would be funny to play football on Mars because the gravity is lovxT.

　　6、If you don't wear special boots,you cannot walk on Mars.

最佳答案:

　　1、Are you aware of the distance from Mars to the Sun?

　　2、Do scientists agree on the possibility of humans living on Mars in the future?

　　3、Have they thought about the problem of low gravity on Mars?

　　4、Are you aware of the transport on Mars?

　　5、I wonder the number of people willing to move to Mars.

　　6、I think people should know the differences of life between on Mars and on the Earth.

最佳答案:

　　1、Mars is a planet with an environment similar to that of the Earth.

　　2、Astronauts in space suits and helmets rrught stay on Mars for hours.

　　3、It is difficult to breathe on a planet with much thinner air than that on the Earth.

　　4、0n Mars there might be people with air tanks on their backs.