get up to something 
phrasal verb with get verb uk/ɡet/ us/ɡet/  getting | got | got or gotten
  UK      
C2 做(常指别人不赞同的事)
to do something, often something that other people would disapprove of
  She's been getting up to all sorts of mischief lately. 她近来老是搞各种各样的恶作剧。 
 I wonder what those two got up to yesterday? 我纳闷儿那两个人昨天都干了些什么勾当。 
 - More examples
 - What have you been getting up to?
 - They got up to all sorts of things on the hen night.
 - What did you get up to on your holiday?
 - She usually gets up to some sort of trouble at school.
 - Tell me what you got up to at the weekend.