weak
单词辨析：
最普通用词，使用范围很广，既可指身体虚弱无力的，也可引申用于力量、意志、权力、性格等方面，表示“薄弱的”、“软弱的”等。
Her mother was weak from a long illness.
她母亲长期患病，身体很虚弱。
I'm very weak when it comes to giving up smoking.
在戒烟问题上我意志很薄弱。
The enemy became so weak that they could not go on with the war.
敌人力量变弱，无法再继续这场战争了。
语气较 weak 强，尤指身体、脉搏、声音等极为虚弱而无力的。
His pulse was too feeble to feel.
他的脉搏太弱了，摸不着。
The newborn baby gave a feeble cry.
那个新生儿哭声很弱。
Her feeble arm dropped powerless to her side.
她那虚弱的胳臂无力地垂在身边。
多指因年迈或生病而身体瘦弱的、虚弱的、衰弱的。
The old man is growing thin and frail.
那位老人日渐瘦弱。
She was still feeling a bit frail.
她仍然感觉身体有点虚弱。
Her frail hands could hardly hold a cup.
她虚弱的手几乎连杯子也拿不住。
相关例句：
That's my weak point.
这正是我的弱点。
She tired easily and had a weak heart.
她很容易疲劳，心脏也不好。
The owner said the bird may have escaped through a weak spot in the aviary
鸟的主人说这只鸟可能是从鸟舍一处不结实的地方逃走的。
Swimming is helpful for bones that are porous and weak.
游泳有助于改善骨质疏松和骨骼脆弱。
Every man has his strong and weak points.
人各有长处和短处。
He is very weak, for he has been ill for a long time.
他病了很久，身体衰弱。