主谓一致
1) 语法形式上要一致,即用作主语的名词中心词和谓语动词在单、复数形式上一致 2) 意义上要一致,即主语和谓语的一致关系取决于主语的单、复数意义.3） 就近原则，即谓语动词的单复形式取决于最靠近它的词语
例题：
1 并列结构作主语时谓语用复数 Reading and writing are very important. 注意： 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，and 此时连接的两个词前只有一个冠词。 The iron and steel industry is very important to our life. The League secretary and monitor ___ asked to make a speech at the meeting. A. is B. was C. are D. were 答案B. 注: 先从时态上考虑.这是过去发生的事情应用过去时,先排除A.,C..本题易误选D,因为The League secretary and monitor 好象是两个人,但仔细辨别, monitor 前没有the,在英语中,当一人兼数职时只在第一个职务前加定冠词.后面的职务用and 相连.这样本题主语为一个人,所以应选B. 2 主谓一致中的靠近原则 当there be 句型的主语是一系列事物时,谓语应与最邻近的主语保持一致. There is a pen, a knife and several books on the desk.. There are twenty boy-students and twenty-three girl-students in the class. 总的来说，在由not only…but also…, not just…but…, or, either…or…, neither…nor…连接主语的句子中及在there be句型中，谓语动词的单复数按就近原则处理，即按与谓语动词最靠近的那个主语来确定谓语动词的单复数形式。如： Not only John but also I am going to Shanghai next week. Either you or she is to go. Here is a pen, a few envelops and some paper for you.
参考资料：来自百度百科