完形填空。 A duck(鸭子) and a hen (母鸡) meet on the road. The duck asks the hen, ' 1 do you work?' The hen answers , ' 2 a farm. ' The duck says , Then you are a 3 . ' ' No, I'm a worker. I make eggs. What 4 you? What do you do?' the hen asks. The duck answers , 'Oh, I'm a 5 . ' The hen asks, 6 do you teach?' ' At a swimming school. ' The hen asks again,' 7 do you teach?' 'I teach swimming. ' ' Oh , good. I want to 8 the sport. Can you teach me?' 'Sorry, I think you can't. '' 9 ?' 'Because you are a hen, you will die(死)in the 10 . ' (     )1. A. Where (     )2. A. In (     )3. A. worker (     )4. A. for (     )5. A. teacher (     )6. A. When (     )7. A. What (     )8. A. have (     )9. A. How (     )10. A. bed B. What B. On B. teacher B. with B. student B. Who B. Why B. learn B. What B. floor C. Which C. At C. farmer C. of C. worker C. How C. When C. teach C. Why C. boat D. How D. To D. student D. about D. farmer D. Where D. Which D. swim D. Who D. water