虚拟语气的问题Somethingmusthavehappenedontheirwayhere.Ortheybynow.A.shouldhavearrivedB.shouldarriveC.wouldhavearrivedD.wouldarrive为什么B不对.我判断的是Somethingmusthavehappenedontheirwayhere是描述

Question

虚拟语气的问题
Something must have happened on their way here.Or they ____ by now.
A.should have arrived B.should arrive
C.would have arrived D.would arrive
为什么B不对.我判断的是Something must have happened on their way here是描述的是对过去事实的推测,但Or they ____ by now应该是对现在的事实的虚拟才对.
另外,为什么用would而不用should.

Answer 1

Something must have happened on their way here.是一个推测,并不是虚拟语气的条件句,所以其实这句话在语法上对后面一句是没什么影响的.后面的则是虚拟语气.
判断出是虚拟语气就可以排除B,D两项,A,C两个皆是虚拟语气,至于为什么答案是C,而不是A,原因是意思的差别.
should have done 的意思一般理解为“本应该”,有“埋怨”的意思在里面,“本来该做的事情没有做”,比如说：I should have gone that way.我本应该走那跳路的.
而would have done 仅是表示与过去事实相反,并没有“应该”的意思,也没有埋怨该做的事情没做的含义.例如：If I had heard the news before,I wouldn't have done this.如果我早知道这则消息,我就不会这样做.
回到原题,很明显,意思是：“他们一定是在来的路上发生了什么事情,不然他们现在已经到这了.” 现实是他们并没有到,所以这里仅仅是陈述与现实相反的意思,并没有“该做的事情没做而埋怨”的意义在里面.答案选C.
我是按照自己的理解讲述的,不过表达起来有点困难,不知道这样说你能不能明白.