题目

根据下面对话中的情景，在每个空白处填入适当的语句，使对话恢复完整。 A: Hi, Mary, I watched a TV show just now about the future. B: Sounds cool. ____________1____________________? A: Well, there will be more computers than books. B:__________________2______________？ A: No, students will study on computers at home. Computers will be much cheaper. B:___________________3______________________? A: No, people won’t use money. Everything will be free in the future. B: This great._________4_____________________? A: The environment will be in great danger. We w在基因工程中，把选出的目的基因（共1000个脱氧核苷酸对，其中腺嘌呤脱氧核苷酸460 个），放入DNA扩增仪中扩增4代，那么，在扩增仪中应放入胞嘧啶脱氧核苷酸的个数是 A．540 个             B．7560个       C．8100 个         D．17280