题目

. Research on the human brain has been attracting more and more scientists in recent years, just like the booming hi-tech industry. One of the latest research topics is how to change the human brain or combine the computer and the human brain, i.e. to transplant a chip into a human brain. This idea may make everyone’s dream come true. If we compare a human brain to a hard disc, what the scientists are doing is to enlarge the capacity of the hard disc. For the time being, there are some difficulties in such transplant experiments, but scientists never give up. Experiments have started on anim5．地铁站台地面上画有黄色的“安全线”，提醒乘客应站在安全线外候车．原因是列车进站时带动周围空气，使车体与候车乘客之间空气流速增大，此处压强小于大气压（选填“大于”或“小于”），容易发生危险．