完形填空。 It's difficult for doctors to help a person with a hurt brain. 1 enough blood, the brain can live only three to five minutes. Usually doctors can't fix the hurt 2 such a short time. Dr Robert White thinks he knows a 3 of help. He thinks doctors should make the hurt brain 4 to live for 30 minutes without blood. This gives the doctor 5 time to do something for the brain. Dr White experimented his 6 on fifteen monkeys. 7 he taught them to do different jobs. Then he operated on them. He made the monkeys' blood go 8 a machine. When the brains' 9 was 10℃, he stopped the blood to the brain. After 30 minutes, he turned the blood back on. He 10 the blood again. After their operations, the monkeys were almost 11 before. They were healthy and busy. Each one could still do the job the doctor 12 them. Dr White's idea works well on monkeys. He thinks it will work on 13 . He think it will help with heart problems. A person 14 die when his heart stops; doctors can 15 it again. The problem comes: when the brain is without blood for about 5 minutes, it 16 . If doctors start the heart again after 5 minutes, the person has 17 body but a dead brain. Maybe in the future, doctors will 18 Dr White's idea. When the person's heart stops the doctor will 19 cool the brain. They will have 30 minutes to start the heart again. Maybe there will be no 20 the brain. (     )1. A. Don't have (     )2. A. for (     )3. A. way (     )4. A. too cool (     )5. A. a longer (     )6. A. medicine (     )7. A. Besides (     )8. A. to (     )9. A. heat (     )10. A. cooled (     )11. A. the same as (     )12. A. was taught (     )13. A. other people (     )14. A. doesn't have to (     )15. A. start (     )16. A. loses (     )17. A. no (     )18. A. get (     )19. A. soon B. Without B. after B. brain B. enough cool B. enough B. manners B. Instead B. across B. temperature B. operated B. different from B. was teaching B. human beings B. needn't B. take B. goes B. a dead B. accept B. quickly C. Having not C. in C. doctor C. cool enough C. a shorter C. idea C. However C. through C. coolness C. warmed C. used to C. was to teach C. other things C. will be able to C. make C. kills C. a living C. keep C. slowly D. Only with D. since D. man D. that cool D. another D. brain D. First D. onto D. feeling D. stopped D. cleverer than D. had taught D. more people D. is afraid to D. begin D. dies D. a lively D. try D. rapid