题目

CCR5是人体的正常基因，其编码的细胞膜CCR5蛋白是HIV-I(人类免疫缺陷病毒I型）感染的“入口”。有研究用“CRISPR/Cas9”技术对该基因进行定点编辑并植入胚胎 （1）将Cas9蛋白和向导RNA序列注入受精卵的方法称为____________________技术。 据图1可知，“CRISPR/Cas9”技术中，首先由具识别序列的________________引导定位至目标DNA序列，然后由Cas9蛋白将DNA切断。这两种物质的作用结果类似于基因工程中______________的作用，若识别序列为……UCCAGAAUC……则DNA对应区域α 完形填空。      In 1971, a young man who grew up very poor was travelling across the country, trying to make a new   1   for himself. Along the way, he had   2   run out of money and was forced to spend the night in his car. This   3   until one morning, after a week of sleeping in his car, he walked   4   into a restaurant and ordered a big breakfast.      After eating his first good meal in   5   , he found himself   6   to the waiter, telling him he had lost his   7   . The waiter, who was also the owner, walked   8   the chair where the young man had been sitting. He bent down,   9   a $20 bill that looked   10   it had fallen on the floor and said,"Son, you must have   11   this," the owner said. The young man couldn't believe his   12   ! He quickly paid for the breakfast, left a   13   , bought gas with the change, and headed West.      On the way out of town, he began to understand   14   the fellow did. Maybe nobody dropped the money  15   ."Maybe that fellow just knew I was   16   and he helped me in a way that didn't  17   me." Right then he made a promise to help others if he could.      Later, he worked very hard and became a rich man. Now, he lives near Kansas City. Each year he  18   thousands of dollars. He is known as the "Secret Santa" because at   19   time each year, he personally hands money out to those on the streets and at hospitals."I've lived the story, so I know it certainly more blessed(带来快乐的) to give than to   20  , because it comes back to you many many times over," he says. "It restores some faith in humanity." (     )1. A. conclusion  (     )2. A. unexpectedly (     )3. A. continued    (     )4. A. hopefully  (     )5. A. hours     (     )6. A. turning   (     )7. A .way       (     )8. A. behind     (     )9. A. took out   (     )10. A. even if   (     )11. A. placed   (     )12. A. luck     (     )13. A. message    (     )14. A. what     (     )15. A. after all  (     )16. A. in danger  (     )17. A. astonish    (     )18. A. gives up  (     )19. A. breakfast  (     )20. A. steal       B. impressionB. completely  B. began    B. nervously  B. weeks    B. lying    B. job     B. near    B. picked out  B. as if    B. put     B. word    B. note     B how      B. above all  B. in pain    B. embarrass   B. sends out  B. Christmas B. provide   C. start    C. strangely    C. spread    C. carelessly   C. years     C. smiling     C. wallet     C. before    C. took up     C. as well    C. dropped    C. promise    C. mark      C. where    C. in all     C. in trouble   C. interest    C. puts away   C. church      C. receive   D. surprise              D. necessarily     D. struggled            D. excitedly           D. months              D. joking              D. car                 D. under               D. picked up             D. even so           D. removed             D. action              D. tip                 D. that                  D. at all              D. in charge              D. discourage       D. gives away        D. New Year              D. rob