虚拟语气是种特殊的动词形式,用来表示说话人所说的并不是事实,而是一种假设、愿望、怀疑或推测。 1. 用if条件从句表示的虚拟条件 | ① 虚拟现在时表示与现在事实相反的假设,if 从句的谓语形式用动词的过去式(be一般用were),主句would/should/could/might+动词原形 | 是虚拟条件最普通的方式 | If I were in your position I would marry her. |
| ② 虚拟过去时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 coul/ might + have +过去分词 | If it had not rained so hard yesterday we could have played tennis. | ③ 大多数的虚拟条件句属于上面三种情况的一种,但并不排除存在条件和后果中,一个和现在情况相反,另一个和过去情况相反 | If you had followed what the doctor said, you would not have been so painful now.这个句子在高中出现频率颇高 | ④ 但是,如果后果用了虚拟语气,而条件却用陈述语气,这种用法是错的。 |
2. 除表示虚假条件外,if从句还可以表示对将来的推测,由于是将来还没有发生的,所以谈不上是真实的还是虚假的,只能说这个事情发生的可能性有多大。 | 一般情况下,可以用陈述语气的if从句来表示对一个未来事实的推测,这个事实是完全可能发生的。 | 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 | Jean doesn't want to work right away because she thinks that if she were to get a job she probably wouldn't be able to see her friends very often. | 3. 有时可把含有助动词、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,这时候如果出现not等否定词,否定词需放在主语后面 | 这种结构口语中很少用,但各类考试出现频率高:If it had not rained so hard yesterday we could have played tennis.→Had it not rained so hard yesterday, we could have played tennis. | 4. 大多数的虚拟条件通过上面所讲的两种方法表达,但在个别句子中也可以通过介词without和介词短语but for表达,副词otherwise等表达出来。 | 例如:We didn't know his telephone number; otherwise we would have telephoned him. | 值得注意:包含but for的句子,谓语动词必定要用虚拟形式,但包含without等短语的句子,谓语动词未必一定要用虚拟语气。 |
用在宾语从句中的虚拟语气 | 1. 在表示愿望的动词wish后的宾语从句中,需用虚拟语气。(wish后的that 常省略),根据主句时态,从句谓语时态相应退后一位,例:How she wished his family could go with him. |
| 2. 在具有愿望、请求、建议、命令等主观意愿的动词(desire, demand, advice, insist, require, suggest, propose, order, recommend, decide …) 后的宾语从句中需用虚拟语气。 |
| 谓语动词用(should) +动词原形。值得注意的是,如果宾语从句的动词是否定的,否定词not的位置应在动词之前,而不是动词之后。 |
| 例如:The head nurse insisted that the patient not be move. |
| 另外suggest表“暗示”,insist表“坚持某种说法”时,后面的从句不用虚拟语气,例:Her pale face suggests that she is ill.或He insisted that he did not kill the boy. |
| ① 在It is+上述动词的过去分词,其后所跟的主语从句中,如It is suggested that pupils wear school uniforms. |
| ② 在上述动词相应的名词形式作主语+连系动词,其后的表语从句中,例如His suggestion was that classed be re-scheduled. |
| ③ 在对上述动词相应的名词进行解释的同位语从句中,如:The workers raised the demand that their pay be increased to cope with the inflation. |
其它形式的虚拟语气 | 1. it is +necessary等形容词后,that主语从句中虚拟形式使用,这类形容词包括necessary, important, essential, imperative, urgent, preferable, vital, advisable等 |
| 例如It is necessary that you listen to the teacher carefully.或者It is essential that you be able to pronounce every single word correctly. |
| 2. 在It's (high/about) time 之后的定语从句中需用虚拟语气。谓语动词用过去式,例如It is high time that you went to school |
| 3. 虚拟语气在as if / as though 引导的方式状语从句中的应用(谓语动词形式与wish后的宾语从句基本相同)表示与现在事实相反或对现在情况有怀疑,谓语动词用过去式。 |
| 例如:He felt as if he alone were responsible for what had happened. 表示过去想象中的动作或情况,谓语动词用过去完成式。 |
| 4. 在lest 引导的状语从句中,谓语动词多用虚拟语气,(should )+ 动词原形。例如: The mad man was put in the soft-padded cell lest he injure himself. |
| 5. 在if only 引起的感叹句中需用虚拟语气。谓语动词用过去式或过去完成式。例如: Look at the terrible situation I am in! if only I had followed your advice. |
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