unpredictable [ˌʌnprɪˈdɪktəbəl]

例句:

• No-one knows where they stand with him; he is utterly unpredictable.
  谁也不知道他怎样看待他们；他是个完全不可捉摸的人。
  来自柯林斯例句
• He is unpredictable, weeping one moment, laughing the next.
  他喜怒无常，一会儿哭，一会儿笑。
  
• She was unpredictable, explosive, impulsive and easily distracted.
  她难以捉摸，脾气暴躁，冲动鲁莽，容易分心。
  
• Other factors could skew the vote in unpredictable ways.
  来自WSJ
• Humor is just too dangerous and unpredictable a weapon.
  来自WSJ
• Do unpredictable players score a higher proportion of penalties?
  来自THETIMES