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.