成眠

nán yǐ chéng mián

难以成眠

can hardly fall into sleep

yè bù chéng mián

夜不成眠

lie awake all night

wǒ yōu xīn chōng chōng bàn yè bù néng chéng mián

我忧心忡忡，半夜不能成眠。

I was awake half the night worrying.

tā wú fǎ chéng mián suǒ yǐ chū qù sàn bù

他无法成眠，所以出去散步。

He could not sleep so he went out for a walk.