second setting

• 定秒装置

second setting的用法和样例：

例句

1. A rule of correspondence between two sets such that there is a unique element in the second set assigned to each element in the first set.
   函数两组元素一一对应的规则，第一组中的每个元素在第二组中只有唯一的对应量
2. Don't forget to take a change of (ie a second set of) clothes.
   不要忘记带著替换的衣服。