A、Ten hours. B、More than ten hours. C、More than nine hours. D、Nine hours. B题目问的是手术持续多久。由定位句可知，五位外科医生要工作超过10小时。故选B。

A baby was undergoing microsurgery last night to save an arm, after his baby carriage was crushed by a tractor.
    Twenty-two-month-old Ryan Millard of Dalton, Texas, was rushed 100 miles to Las Vegas’ s Cummington Medical Center after the accident near his home.
    It took more than ten hours for five surgeons, working through the night, to sew back Ryan Millard’s left arm.
    The 22-month-old baby woke up only minutes after the operation, doctors said. Now his parents wait to see if the incredibly complex and difficult operation has been a complete success.
    After Ryan’ s arm had been broken into two parts, they were packed in ice for the journey to Cummington. Ice keeps a broken limb usable for valuable hours longer so that surgeons have a chance to sew it back.
    Now that Ryan has gone through all this, what are his chances of making a complete recovery? About 60 to 40 percent, the doctors said.
    Q22: What is the talk mainly about?
    Q23: What happened to the baby?
    Q24: How long did the operation last?