助动词(auxiliary verbs or helping verbs),顾名思义,帮助动词的词。从这个意义上看,情态动词(modal verbs)也应属于助动词范畴。在英语中,我们通常把be、do、have这三个词当作助动词进行讲解。 既然是“帮助”,当然是处于辅助地位,否则将喧宾夺主。因此,充当助动词时be、do和have在句子没有词义,只具有语法意义。 在讲解这三个助动词之前,请明确一点:它们来“帮助”动词,不是“可帮可不帮”,而是“非帮不可”!下面我们来详细说说,这个三个助动词分别都能帮助动词做什么? 一、助动词be1、帮助构成进行时态:结构为be+现在分词(简记:be doing)。通过变换be的形式(am, is, are; was, were; will be),分别构成现在进行时态、过去进行时态和将来进行时态。请看例句: 例句1:I am watching TV with my parents at home. (现在进行时态) 例句2:He is playing the piano in his room now.(现在进行时态) 例句3:They are playing football outside.(现在进行时态) 例句4:He was walking along the road when I met him.(过去进行时态) 例句5:They were swimming happily in the pool then.(过去进行时态) 例句6:I will be waiting for a friend from Shanghai at the train station then.(将来进行时态) 2、帮助构成被动语态:结构为be+过去分词(简记:be done)。通过变换be的形式,可构成如下时态的被动语态: ①:一般现在时被动语态:即am/is/are+过去分词 例句7:Trees are planted there every year. ②:一般过去时被动语态:即was/were+过去分词 例句8:The bridge was built about 20 years ago. ③:一般将来时被动语态:即will be+过去分词 例句9:My homework will be finished in 10 minutes. 以上为一般时态下的三种常见被动语态形式。另外:进行时态被动语态,结构为:be being done;完成时态的被动语态,结构为:have been done;完成进行时态的被动语态,机构为:have been being done。这部分内容将在时态和语态部分详细论述。 二、助动词do1、帮助构成否定句 在“主语+谓语+(宾语)”结构中,肯定句变否定句的方式为:在句中谓语动词前加don't,doesn't或didn't。即从“主语+谓语+(宾语)”变为“主语+谓语+(宾语)”。请看例句变化: 例句10:I have a car. → I don’t have a car. 例句11:She likes swimming. → She doesn’t like swimming. 例句12:He bought a bike yesterday. → He didn’t buy a bike yesterday. 注:在“主语+系动词+表语”结构中,如果系动词不是be,那么变否定方法如上所述。比如:He looks young. 变否定句,变为:He doesn't look young. 2、帮助构成一般疑问句 在“主语+谓语+(宾语)”结构中,变一般疑问句时:直接在句首加Do,Does或Did;句子中如果有第一人称代词变为第二人称代词(一变二)。请看例句: 例句13:I have a car. → Do you have a car? (谓语动词原形用do) 例句14:She likes swimming. → Does she like swimming? (谓语动词三单用does,谓还原) 例句15:He bought a bike yesterday. → Did he buy a bike yesterday? (谓语动词过去式用did,谓还原) 3、帮助加强语气 通常,在一般现在时和一般过去时的句子中,在谓语动词前加do,does或did,用来加强语气,这时可翻译为:“的确”、“确实”等。请看下面对话: A:Do you need a pen? 你需要一支钢笔吗? B:Yes, I do need one. 是的,我确实需要一支。 do用来加强语气的这种用法不复杂,在具体语境中遇到时,注意理解为何要加强语气,以便读出句子的“意外之意”。 三、助动词havehave作助动词时,用法比较单一,只能用来帮助动词构成完成时态,结构为have+过去分词(简记:have done)。通过变换have的形式,可构成如下三种完成时态(这里没讨论过去将来时态): 1、have/has done:现在完成时态 例句16:I have finished my homework, so I can watch TV for some time. 2、had done:过去完成时态 例句17:The train had left when I got to the station. 3、will have done:将来完成时态 例句18:We will have lived in the city for about 30 years by the end of 2019. be、do、have这三个词除了作助动词外,本身它们都是可以用作实义动词的。这一点要牢记!所以,在具体语境中,要首先判断它们是作助动词,还是用作实义动词,作谓语的。 感谢阅读本文!美图分享,缓解疲劳~~~ |
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