四、单复数同形的名词作主语时, 主语与谓语动词的一致

　　单复数同形的名词作主语时, 要根据句子意思来确定谓语动词的单复数形式,单复数同形的名词包括: aircraft, deer, fish, sheep , means, species, series, works, crossroads headquarters等。

　　Various means of transport are introduced in this article.

　　There are already 137 species of butterflies known in the world today.

　　It is all a means to an end.这只是达到目的的一种手段。

　　The airline ordered 15 new aircraft.那家航空公司订购了十五架新飞机。

　　五、表示时间、距离、度量、价值的复数名词作主语时,主语与谓语动词的一致

　　这些复数名词, 如表示抽象概念, 被视作一整体时,谓语动词用单数形式;如表示具体的多少, 强调复数意义时,谓语动词用复数形式。

　　Ten minutes is all that I can spare for you.

　　Six thousand dollars is a large sum of money to her.

　　The fifty miles were covered by the winner in three hours.

　　六、由with, as well as等词或词组修饰的单数名词作主语时,主语与谓语动词的一致.

　　如作主语的单数名词后有下列词或词组修饰时, 谓语动词仍用单数形式: with, along with, together with, besides, as well as, in addition to, accompanied by, rather than, but等。

　　The teacher as well as the students likes this novel.

　　A scientist, together with some assistants,was sent to help solve that problem.

　　The boss, rather than his employees, is to blame.

　　Nobody but San and Ann is in the lab.