主谓一致是指句子中的主语和谓语在人称和数上要保持一致。以下是主谓一致的语法总结:
语法一致原则
单数主语用单数谓语动词,例如:The book is interesting.
复数主语用复数谓语动词,例如:The books are interesting.
意义一致原则
集体名词(如family, class)在强调整体概念时,谓语动词用单数;若强调个体成员,则用复数。例如:Ten years is a long time.
就近一致原则
由or, either...or..., neither...nor..., not only...but also...等连接的并列主语,谓语动词与靠近它的那个主语保持一致。例如:Either you or he is right.
特殊情况
不定式、动名词及从句作主语时应看作单数,谓语动词用单数。例如:To learn a new language is exciting.
不定代词及each作主语或是修饰主语时应看作单数,谓语动词用单数。例如:Everyone should do their best.
表示国家、机构、事件、作品等名称的专有名词作主语时应看作单数,谓语动词用单数。例如:The United States is a great country.
a series of, a kind of, the number等短语作主语时,谓语动词通常用单数。例如:A series of events led to the decision.
并列结构
当主语由and连结时,如果它表示一个单一的概念,即指同一人或同一物时,谓语动词用单数。例如:The iron and steel industry is very important to our life.
如果主语由and连结,但表示两个或两个以上的概念时,谓语动词用复数。例如:Reading and writing are very important.
代词
代词all, half, most, the rest等以及“分数或百分数+名词”作主语时,谓语动词的单复数取决于连用的名词。例如:Three-quarters of the students passed the exam.
从句
当主语是what从句时,如果表语是单数,主句的谓语动词一般用单数;如果表语是复数,主句的谓语动词一般用复数。例如:What caused the accident is a complete mystery.
通过以上总结,可以更好地理解和应用主谓一致的原则,使句子在语法和意义上保持一致。