1.Now that you mention it, she did seem to be in a strange mood.既然你说到这事儿，她确实好像情绪不大对。
2.They are hoping for a return to normality now that the war is over.既然战争结束了，他们希望一切都恢复常态。
3.Now that the problem has been identified, appropriate action can be taken.现在既已找出问题的症结，即可采取适当行动。
now that既然，由于，引导原因状语从句。例如:Now that you are a student,you should study hard.
