true time的用法和样例：
例句
- A transition is only performed when its associated condition is true.
转移只在其相关联的条件为真时才执行。 - Inventors created sundials, which indicate time by the length or direction of the sun's shadow, to track temporal hours during the day.
当时的发明家制造了日晷，利用太阳阴影的长度或角度，来测量白天真时的变化。
