Ⅰ、 1、 by the year of 2100
2、 at the moment
3、become more and more crowed
4、 at the speed of light
5、three-eighths of
6、so that
7、float off into space
8、in some ways
9、 in the form of pills
10、 compared with life on the Earth
Ⅱ、1、planets
2、 crowded; polluted
3、transports
4、 floating
5、Compared
6、humans
7、population
8、gravity
Ⅲ、1-5 BBDAD
6-8 CDA
Ⅳ、 1、 think of; on another planet; How; on another planet
2、 will be; pollution
3、thought; liked
4、 Humans; food;water; oxygen to survive
5、Too much food; feel ill
6、gravity; one-sixth; that
Ⅴ、 1-5 DACDB
6-10 CBACD
Ⅵ 、1-5 CBBAC