有位老师正在上血液循环课,为了要解释得更清楚,他说“:同学们,如果我现在倒立,血液就会跑到头里去,我的脸就会变红。”“那么,老师,”男孩问.“为什么我们以平常的姿势站立时,血液不会跑到脚里去?”一个小男生大声说道:“那是因为你的脚不是空的.”A teacherw as giving a les A teacher is on the blood circulation class. In order to explain it more clearly, he said, “Classmates, if I were to stand upright now, the blood would run to my head and my face would turn red.” “Then, teacher, The boy asked. ”Why don’t the blood go into the foot when we stand in the usual posture?“ a little boy said loudly, ”That’s because your feet aren’t empty." A teacherw as giving a les