act up

phr

• ① 【口】行为不良,出乱子;出毛病
  • The pupils always act up when the teacher is away.老师离开时,那些学生总是捣乱。

• ② (机器等)出毛病;(症状等)恶化
  • The car is acting up again.汽车又出毛病了。