I'm off to bed.
强调上床是要去休息
I finally succeeded in packing her off to bed.
最后我总算是把她打发上床睡觉了。
It's bedtime. 睡觉时间
Put your toys away now, it's bedtime.
把玩具放好，该上床睡觉了。
I'm going to hit the sack.
sack在这里是指床，hit是去床上睡觉的意思。
I've got a busy day tomorrow, so I think I'll hit the sack.
明天我将度过繁忙的一天，因此我得上床去睡觉了。
I'll retire for the night.
俚语用法：准备去睡觉
It was getting late, they prepared to retire for the night.
夜已深，他们便准备就寝了。
