题目

阅读理解 Only about 30 percentof people in the US know how to perform CPR (心肺复苏术).Recently, a 9-year-old boy showed a Georgia woman how to perform CPR on hernewborn baby. Susanna Rohm said shehad experienced a parent's worst nightmare (噩梦) — her 2-month-oldson, Isiah, was not breathing. I noticed he looked pale. I looked at hisarms and his legs and they were limp (无力的), Rohmtold a local newspaper. Then I noticed that he looked like he wasn'talive. Indismay, she dropped and broke her cellphone. Rohm had torun into the street, screaming for help. I had him in myarms and1．通讯员从一列长为L的沿直线公路前进着的队伍排尾出发，追到排头后又返回排尾，在他往返一次的这段时间内，队伍前进的距离是5L，则通讯员的位移大小是5L．