weak local extremum

例句：

1. 1. The old man is weak and needs to rest more often.
   老人身体虚弱，需要经常休息。
2. 2. The baby was weak and couldn't walk by himself.
   婴儿身体虚弱，不能自己走路。
3. 3. The team was weak in defense, which cost them the game.
   球队在防守上表现薄弱，导致输掉了比赛。