check-in

例句：

1. 1. 登记入住；2.签到；3.
   飞机、火车等的
2. 1. Please check in at the counter when you arrive.
   请到达时在柜台办理入住手续。
3. 2. She checked in to the hotel and was given a key.
   她办理了酒店入住手续并拿到了钥匙。
4. 3. The airlines require passengers to check in at least two hours before departure.
   航空公司要求乘客至少在出发前两小时办理登机手续。