check in/check into something        
phrasal verb with check verb uk/tʃek/ us/tʃek/
B1 (在酒店等)办理入住手续;登记,报到
to say who you are when you arrive at a hotel so that you can be given a key for your room
  Please would you check in at the reception desk and sign your name in the book. 请您在接待处报到,并在登记簿上签名。 
 - More examples
 - When we had checked in, the desk clerk gave us our key.
 - We then checked into the hotel for a weekend of unashamed luxury.
 - After driving all day, I was so pleased just to check into a motel and relax.
 - The police wanted to know whether any new guests checked in on Sunday evening.
 - An elderly couple checked into Room 8 about an hour ago.