虚弱的

例句：

1. 1. The old man was weak from lack of sleep.
   老人因为缺乏睡眠而虚弱。
2. 2. The baby is too weak to walk yet.
   这个婴儿还太小，还不能走路。
3. 3. The old tree is weak and needs support.
   这棵老树很弱，需要支撑。