I have a busy day tomorrow, so I think I'll hit the sack.明天我会很忙，所以我看我该睡觉了。I'm off home to hit the sack.我回家睡觉去了。Louis was so tired that he hit the sack soon after supper.路易斯十分疲劳，吃过晚饭就上床睡了。It's time to hit the sack. 现在该睡觉了。It's one o'clock – time to hit the sack.一点钟了 — 该睡觉了。