they're       
uk/ðeər/ us/ðer/
 (they are 的缩略形式)
short form of they are
  They're so in love. 他们如此相爱。 
 - More examples
 - They're going to move house soon.
 - She said that they're planning a camping trip.
 - I hope they're not disappointed.
 - They're all members of the same family.
 - I don't know if they're on their way yet.