for+时间段 ,since+时间点 ,by+将来的时间 ,lately；recently,just,up to now,till now,so far,these days,in the past few years／months／weeks／days ,yesterday；last week；in 1945,at that time；once；during the war；before；a few days ago；when,used to+动词原形,be／become／get used to+动名词doing,before,after,by,up till ,will do.will be doing,have been doing