hook up           
phrasal verb with hook verb uk/hʊk/ us/hʊk/
 informal与(他人)接触,与(他人)一起工作 
to meet or begin to work with another person or other people
  He hooked up with the other members of the band in Amsterdam. 他在阿姆斯特丹结识了乐队的其他成员。 
  informal与(某人)开始一段恋爱(或性)关系 
to begin a romantic or sexual relationship with someone
  When did you two first hook up? 你们俩是什么时候开始在一起的?