阅读理解。 Spread out a map of the world. What you see on it depends on the kind of map you have. Does it show cities and countries? Mountains and valleys? Maybe weather patterns? The variety of features is so great that one map just can't handle them all. The earth is part of a nine planets solar system within the Milky Way galaxy. Its size and location aren't very impressive. We inhabit the third planet from the Sun, which is only the fifth largest overall. Yet The earth has a talent for creating life. In fact, it's the only place that has life so far! One form of life humans tends to take this for granted. Human activities like habitat destruction, pollution, and over-fishing have badly damaged life as we know it. Luckily, Earth is as tough as it is beautiful. But it doesn't take an expert to see that one planet can only take so much. 1. In the _____, there are _____ planets in all. [     ] A. Milky Way galaxy; 7 B. solar system; 8 C. solar system; 9 D. Milky Way galaxy; 10 2. The earth is the _____ largest planet in the solar system and the _____ planet from the Sun. [     ] A. fifth; third B. third; fifth C. second; third D. third; sixth 3. As is known to us all, _____ has badly damaged the earth life. [     ] A. habitat destruction B. pollution C. over-fishing D. all of the above