桃花谢了，有再开的时候。

If peach blossoms fade, they will flower again.

youdao

桃花谢了，有再开的时候。

The peach blossoms are over.

youdao

杨柳枯了，有再青的时候；桃花谢了，有再开的时候。

Willows dry up, they will be green again, Peachblossoms fall, they will bloom again.

youdao

If the temperature drops below a certain level it sends a signal, 'turn on the heat', and that signal stays on until it gets a negative signal to turn off.

如果温度降到一定程度以下时,探测器会发送一个信号,打开加热器,直到加热器再收到关闭的信号,它就会一直开着

耶鲁公开课 - 生物医学工程探索课程节选