题目太多了，应该把握解题方式，一般情况下for+一段时间或者since+时间点的句子都用现在完成时，所有的短暂性动词全部要转换成延续性动词，假如是表示动作的持续性哪就用现在完成进行时。如theoldmanhasdied.theoldmanhasbeendeadfortwoyearsshehasbeenwritingnovelsfortwoyears,uptonowshehasfinishedthirtynovels.