[xiào lì]
（效劳） render a service to; serve
（事物所产生的有利作用） potence; effect; efficacy
The drug has lost its potence by being exposed to moisture.
这药因受潮失去了效力。
（约束力） force; effect; avail
Both texts are equally authentic.
两种文本具有同等效力。
efficiency; efficacy; effectiveness; vigour; muscle; function