就像其它系统一样，这个系统是高度易变的（有些人的生理系统很虚弱，有些人的很强健），而且随着年龄的增长，这种理能会逐渐被耗尽、变的虚弱。

Like any other system, it is highly variable (some people have weak systems, some people have strong systems), and it wears out and gets more fragile with age.

youdao

他身体强健，但精神虚弱。

He is strong physically, but weak mentally.

youdao

片刻前，我还是那么虚弱、疲乏，闷闷不乐，而吸了这仙界的补汁以后，瞧我强健得象一只雄鹰。

For note how faint and weary and heart-sick I was a minute ago; well, I suck this celestial cordial, and now behold me as strong as an eagle.

youdao

片刻前，我还是那么虚弱、疲乏，闷闷不乐，而吸了这仙界的补汁以后，瞧我强健得象一只雄鹰。

For note how faint and weary and heart-sick I was a minute ago; well, I suck this celestial cordial, and now behold me as strong as an eagle.

youdao