1．―你看上去很紧张，发生了什么事？   
      —我不知道怎样回答这个问题。   
      You_______  _______.What happened? I don't know how to answer the question.
2．―你看上去很高兴，有什么事吗？  
      ―老师告诉我通过考试了。   
      You________  ________  _______very happy. What's the matter?   
      My teacher told me that I passed the exam.
3．我不知道是否应该告诉我妈妈真相。
      I_______  ________  _______I should tell my mother the truth．
4．我不明白为什么我的老板不让我去美国。
      I_______  _______  ________my boss didn't let me go to Amerlca.
5．起初，他非常害怕上学。  
      He was very________  _________  ________to school at first.