【正文】
Unit 1 Life on Mars Reading What problems does Earth have? crowded polluted The reasons for moving to Mars. Transport to Mars. Needed things on Mars. Gravity problem. Main idea of each paragraph Para 1 Para 2 Para 3 Para 4 Para 5 Para 6 Para 7 Home on Mars. Schooling on Mars. Disadvantages on Mars transport Spacecraft. Space shuttles. 1 How do people go to Mars at present? And how long does it take? Months. 2 How will people go to Mars by the year 2100? And how long will it take? Only a very short time. Food, water and air 4 What will scientists do They will develop plants that can grow on Mars 3What do humans need to survive? Food, water and air Yes, it is. Because the gravity on Mars is threeeighths of the gravity on Earth. People may jump high easily and float away into space. Peopl