力不能支

nà nián qīng rén shǒu zhǐ jìng luán zhe hū rán lì bù néng zhī shì de guì dǎo zài chuáng qián

那年轻人手指痉挛着，忽然力不能支似的跪倒在床前。

The young man's fingers were twitching, and he suddenly fell to his knees before the bed, unable to lift himself.