infirmness

例句：

1. 1.The old man was infirm enoughto need a wheelchair.
   老人虚弱到需要轮椅。
2. 2. She felt infirm after thelong flight.
   长途飞行后她感到虚弱。
3. 3.His health is infirm, and heneeds to rest more often.
   他的健康不佳，需要更频繁地休息。