短语词组短语LEAP SECOND PENDING STATUS 闰秒等待状态positive leap second [天]正闰秒negative leap second [天]负闰秒leap second adjustment 闰秒调整second leap -over 二次跨越a second leap 二次飞跃the second leap 第二个飞跃the second historical leap 第二次历史性飞跃 返回 leap second