英语高手请进,主谓一致问题

1。A 原因：在一些短语,如 many a 或 more than one 所修饰的词作主语时,谓语动词多用单数形式。但由more than… of 作主语时,动词应与其后的名词或代词保持一致。Many a person has read the novel。许多人都读过这本书。More than 60 percent of the students are from the city。百分之六十多的学生都来自这个城市。2。B 原因：由or,either。。。or。。。,neither。。。nor。。。,not only。。。but also。。。,not。。。but。。。等连接并列主语时,谓语动词的数通常遵循“就近一致”的原则,即谓语动词的单、复数形式依最接近它的主语而定。特别要注意疑问句中谓语动词的形式。如:Either her father or her mother calls for her every afternoon。－ Are either you or he to go there － Neither is。Neither the president of the company nor the sales manager is a college graduate。3。B 原因：一些以-ics结尾的学科名词,如mathematics /politics / physics以及news/works(工厂)/means等在形式上似乎是名词的复数形式,但多用作单数名词,此类名词作主语时,谓语动词一般使用单数形式。如:The paper works was built in 1990。Every possible means has been used to prevent the air pollution,but the sky is still not clear。