第1个回答 2013-08-31
1、在错综条件句子中,虚拟条件从句和主句动作发生的时间不一致,因此,主句和从句的谓语动词应根据所指的时间选用适当的虚拟语气形式。例如: 1)If I were you,I wouldn't have missed the film last night.如果我是你,我就不会错过昨天晚上的那部电影。(从句与现在事实相反,主句与过去事实相反。) 2)If he had followed the doctor's advice,he would recover already.如果他遵照医生的劝告,现在病就好了。(从句与过去事实相反,主句与现在事实相反。) 2、在if虚拟条件句中,有时可把连词省去,采用倒装语序把谓语动词were或助动词did,had,should移到句首构成非真实条件从句的另一种句型,其意思不变。例如: 1)Had we time to spare,we would be glad to go to the park.如果能抽出时间,我们很乐意逛公园。 2)Were it not for the discovery of electricity,the modern world would experience great inconveniece.假如没有发现电,现代世界将很不方便。 3、有时假设的情况不用if引导虚拟条件从句来表述,而用介词(如without, but for等)引出的短语、分词(如supposing等)引出的短语、并列连词(如or,otherwise,but,though等)、由动词suppose引出的祈使句或通过上下文的意思来表达。此时句中谓语动词仍采用虚拟语气的相应形式。例如: 1)But for your advice,I would not be able to do this work.要不是你的劝告,我是不会做这份工作的。 2)Victor obviously doesn't know what's happened,otherwise he wouldn't have made such a stupid remark.显然维克多不知道发生了什么事情。不然的话,他就不会说这样愚蠢的话了。 4、在一些表示愿望、建议、请求、命令等含义的动词后面的宾语从句中,谓语动词用动词原形或"should+动词原形"表示虚拟语气。这类动词有ask,demand, insist,order,propose,move,desire,require等。例如: 1)They demanded that the aggressor troops(should)be withdrawn immediately.他们要求立即撤出侵略军。 2)I moved that he(should)be discharged for his serious mistake.我建议,由于他犯有严重错误,应解除他的职务。 5、在"would(had)rather(would sooner,would as soon)+宾语从句"句型中,要求后面的宾语从句用虚拟语气。但这种虚拟语气表示的不是与事实相反的假设,而是一种尚未实现的愿望,其从句谓语动词用一般过去时。例如: 1)I would rather you came next Friday.我希望你下周五来。 2)I'd just as soon you didn't speak rudely to her.我真希望你别对她那么粗鲁地讲话。 6、在和idea,necessity,plan, motion,order,proposal,recommendation,suggestion,under- standing等词有关的同位语或表语从句中,谓语动词用动词原形或"should+动词原形"表示虚拟语气。例如: 1)M y idea is that the group(should)hold another session to discuss the problem.我的意见是小组召开另一次会议来讨论这个问题。 2)Emphasis is laid on the necessity that all the objectives to be attained be taken into account before starting a new project.我们强调在开始制定一个新的计划之前,必须把要达到的所有目标都考虑进去。 7、在某些"It is+形容词+that..."句型中,如"It is important(necessary,essential, natural,desirable,unusual,pity,strange)that...",that所引导的主语从句中谓语动词均用动词原形或"should+动词原形"来表示虚拟语气。例如: 1)It is highly desirable that a new president be appointed for this college.人们迫切地希望能给这个学院派一个新院长。 2)It is strange that the girl(should)be so arrogant.真奇怪,这个女孩竟会如此傲慢。 8、在"It is ordered(suggested,demanded,moved,planned等)+that..."这个句型中,that引导的主语从句要用虚拟语气形式,谓语动词用动词原形或"should+动词原形"。例如: 1)It is moved that Lucy give a performance at the party.有人提议露茜在晚会上表演一个节目。 2)It was suggested that more teachers (should)be sent there to help them.有人建议派更多的老师去那儿帮助他们。 9、as if /though可以引出一个状语从句也可以引出一个表语从句。当as if/though跟在be,feel,look,seem,sound等系动词之后时,引导的是表语从句;如果主句的谓语动词不是联系动词be等,as if/though引导的则是方式状语从句。无论是哪种类型的从句,只要从句的内容是不真实的,都必须用虚拟语气。当从句表示与现在的事实相反,谓语动词用一般过去时;表示与过去事实相反要用"had+过去分词";表示与将来可能相反的则用"would(could,might)+动词原形"。例如: 1)I feel as if I were going to faint.我感到我像要昏过去似的。(与现在事实相反的表语从句) 2)She cried as if her heart could be broken.她哭的好像心都要碎了。(与将来可能相反的主语从句) 10、在It is(about /high)time引导的定语从句中,也可以根据需要使用虚拟语气,用以表示"(此刻)该做……而没有做"的意思,其谓语动词用过去时或"should+动词原形(用should时,不能将其省略)"。例如: 1)It is time I should leave.我该走了。 2)It is about time that you got(should get) dressed.你该穿衣服了。 11、if only引导的是省略了表示结果的主句的虚拟结构,现在已成为惯用法,表达愿望。从句用过去时表示现在没有实现的愿望;对过去没有实现或不能实现的愿望,从句就用过去完成时。这类句型表示一种不真实的条件,常译成"要是……就好了!"例如: 1)If only I had taken mother's advice.我要是听取妈妈的建议就好了。 2)If only I could speak several foreign languages.我要是能讲几种外语就好了。 12、在以in order that,so that,lest引导的目的状语从句中,谓语动词一般用虚拟语气。从句中的谓语动词用"may(might)+动词原形"或"should+动词原形"。在以lest引导的从句中,谓语动词用"should+动词原形"。例如: 1)She stayed at home for a few days so that she might take care of her sick mother.她在家里呆了好几天,以便能照顾生病的母亲。 2)The teacher explained the sentences again and again in order that the students could understand them clearly.老师一再解释这些句子以便学生能够清楚地理解。