虚拟语气在条件状语从句中的应用

<BR><BR>虚拟语气(Subjunctive Mood)这一语法项目几乎是四、六级必考的内容，也是各类英语考试中心测试的重点之一。虚拟语气是一种特殊的动词形式，用来表示说话人所说的话并不是事实，而是一种假设、愿望、怀疑或推测。<BR>　　1. 虚拟现在时表示与现在事实相反的假设，其if 从句的谓语形式用动词的过去式(be 一般用were)，主句用would/ should/ could/ might +动词原形。<BR>　　1) If places ______ a like, there would be little need for geographers.<BR>　　A. being 　　B. are 　　C. be 　　D. were<BR>　　如果各个地方都一样，就不需要地理学家了。(答案是D)<BR>　　2) If I _____ the meaning of the word, I wouldn't have to look it up.<BR>　　A. know 　　B. knew 　　C. known 　　D. knowing<BR>　　如果我知道这个词的意义，就不必查词典了。（答案是B）<BR>　　2. 虚拟过去时是表示与过去事实相反的假设，if 从句的谓语形式用过去完成时即had＋过去分词，主句用would / should / could / might + have +过去分词。<BR>　　例：1995年6月四级第46题<BR>　　We didn't know his telephone number, otherwise we _____ him,<BR>　　A) would have telephoned 　　 B) must have telephoned <BR>　　C) would telephone 　　　　　 D) had telephoned <BR>　　本题是与过去时相反的虚拟句，从句中用过去完成式，主句中用would have done。本句相当于if we had known his telephone number，we would have telephoned him。答案是A) would have telephoned。 <BR>　　3. 虚拟将来时是表示对将来实现的可能性很小的或不确定的假设。If从句的谓语形式用一般过去式或用were to / should +动词原形，主句用would / should /could/ might +动词原形。<BR>　　例：1996年1月四级第44题<BR>　　Jean doesn't want to work right away because she thinks that if she ______ a job she probably wouldn't be able to see her friends very often.<BR>　　A. has to get 　　B. had got 　　C. were to get 　　D. could have got<BR>　　本句的意思是：“琼不想马上就工作，她认为要是找了工作，就不能经常探访她的朋友了”。 这说明，琼目前没有工作。句中假设的情况在近期内并不会存在。该条件句应当用表示将来情况的虚拟语气。 条件从句的谓语用should或were to引出。 因此C. were to get 是本题答案。选项A. has to get是陈述语气的现在时，不能用于虚拟条件句中。选项B. had got是虚拟语气的过去时，不能表示将来时间。选项D. could have got不能用于虚拟语气的条件从句中.<BR><BR>4. 省略if 采用倒装语序的条件句。<BR>　　有时可以把含有助动词、情态动词、be或have的虚拟条件句中的连词if 省去，而将had , should, were 等词提到主语之前，即用倒装结构。（这种结构在口语中很少使用）。<BR>　　例：1997年6月四级第42题：<BR>　　Had he worked harder, he _____ the exams.<BR>　　A. must have got through 　　　 B. would have got through<BR>　　C. would get through 　　　　　D. could get through<BR>　　本题前半句是表示与过去事实相反的虚拟条件从句，后半句是表示与过去事实相反的主句。相当于：If he had worked harder, he would have got through the exams.本题的答案是B. would have got through。选项A. must have got through（肯定通过）表示一种对过去事情的主观推测，不是与过去事情相反的情况。另外，must不能用在虚拟条件句中。选项C. would get through（就会通过）是虚拟语气现在时的一种表示方法，表示与现在事实相反。选项D. could get through（可能通过），could也可以用于非真实条件句里，表示与事实相反的情况，但这里，它只表示与现在事实或将来可能的事实相反。<BR>　　5. 有时虚拟条件句并没来if 从句表示出来，而是用介词短语、上下文或其它方式来表示。<BR>　　例：1995年6月四级第46题<BR>　　We didn't know his telephone number; otherwise we __________ him.<BR>　　A. would have telephoned 　　　 B. would telephone<BR>　　C. must have telephoned 　　　　D. had telephoned<BR>　　结合选项可知, 全句的意思是：“我们不知道他的电话号码，否则我们会打电话给他”。本句中otherwise 引出的是一种与过去事实相反的假设条件， 即实际上没有打电话，因此应选A. would have telephoned。全句相当于：If we had known his telephone number, we would have telephoned him. 选项B. must have telephoned中“must + 完成式”表示“必定……”。选项C. would telephone 的意思是“会打电话”。 因为本题是讲过去发生的情况， 实际上没有打电话，所以不能用would telephone。选项D. had telephoned表示“已经打过电话”，但本题的意思是“没有打过电话”， 所以 D 不是答案。