Question

20．他离开实验室已经不止一小时了．
He has been away from the lab for over/more than an hour．．

Answer 1

分析 He has been away from the lab for over/more than an hour．

解答 答案：He has been away from the lab for over/more than an hour．这是一个陈述句，离开这个动作发生在过去，持续了不止一个小时了，用现在完成时have/has+过去分词，主语是三单he，故has，离开leave是一个短暂性动词，这里是和一段时间for over/more than an hour不止一小时连用，需换成be away from表状态，be的过去分词是been，实验室the lab，故答案是He has been away from the lab for over/more than an hour．

点评 这里是现在完成时，本题要注意要短暂性动词转换成持续性动词，这里是用be+形容词或副词替换短暂性动词． 
  die→be dead，leave→be away（from），finish/end→be over，begin/start→be on，open→be open，close→be closed，come here→be here，come back→be back，marry→be married，fall asleep/get to sleep→be asleep，return→be back等