完形填空。 No air means death (死). 1 we can't see it, there is air around us. So air is everywhere and it 2 life to every 3 thing. 4 it we can't live. Bad air makes people ill. We must have fresh air to keep us in good health.In the city there are a great many people and there are too many cars 5 on the road. The gas which the car sends out is made up of bad gases. Every day we breathe it in and 6 . This makes us 7 sick. So people should go out of the door as much as they can. There are many factories, too. From the chimneys (烟囱) of these factories, we get the smoke usually in black color. This kind of smoke is dangerous 8 our health. So in order to keep us 9 , we have to go out to the countryside to 10 more fresh air. Or we can climb up hills to get more fresh air. (     )1. A. Or (     )2. A. gives (     )3. A. live (     )4. A. With (     )5. A. run (     )6. A. out (     )7. A. feel (     )8. A. to (     )9. A. health (     )10. A. breathes B. But B. gave B. lives B. Without B. to run B. outside B. feeling B. with B. well B. breathe C. Though C. giving C. lived C. In C. running C. off C. to feel C. about C. healthy C. breathing D. When D. given D. living D. Off D. ran D. away D. felt D. for D. better D. breathed