maximal expiratory flow in 50% vital capacity

例句：

1. 1.The maximal value of the function is 50% of its maximum possible value.
   函数的最大值是其可能最大值的50%。
2. 2. The maximal distance between two points on a line is the length of the line segment joining them.
   两点之间的最大距离是连接这两点的线段的长度。
3. 3. The maximal temperature reached during the day was 40°C.
   白天达到的最高温度是40°C。