sign off
1． mark the end of a radio or television programme for the day结束广播
This is your favorite announcer signing off for tonight．这是你最喜欢的播音员在结束今晚的广播。
The local station signs off at midnight．地方台午夜停止广播。
2．end a letter结束书信
I must sign off now．Love，Mary．就止停笔。爱你的，玛丽。
3．stop work for the day停止工作
Because of the snow，we signed off at three o'clock．由于下雪，我们3点钟就下班了。
The man signed off work at half past six．那人在6点半下班。