a quantity of / quantities of 的用法区别

a quantity of+名词和quantities of+名词做主语时，谓语动词用单数还是复数，不同的参考书有不同的说法，请问究竟该怎么用？

答：该问题主要涉及的知识点为：quantity 与后面谓语动词单、复数搭配(即主谓一致)。但是关于quantity 与谓语单复数搭配，现在说法不统一。主要有两种观点：

1、与词形保持一致

a quantity of /quantities of 不管后面接复数还是单数(包括不可数)名词，只看quantity 本身。即：a quantity of 中的quantity 是单数，谓语动词就用单数；quantities of 中quantities 是复数，谓语动词则与复数保持一致。例如：

Quantities of nuts were on the table.

A quantity of nuts was on the table.

2、与意义保持一致

这种观点认为，不应该看a quantity of / quantities of 本身，而应该看这个词组后面所接的是什么名词，如果后面的名词是单数(或不可数)，则谓语用单数；如果名词是复数，那么谓语用复数。这一点与a lot of 相同，即遵循意义一致原则。例如：

There is only a small quantity of wine left.

Great quantities of sand was washed down the hillside by the rain last night.

A large quantity of air conditions have been sold since the summer came.

Huge quantities of oil were shipped to Japan last year.

结论：目前，比较倾向于与quantity 的词形保持一致，即 a quantity of 是单数，quantities of 是复数，而不管后面接单数或复数的名词。例如，某省一道高考题如下：

With many forests being destroyed, huge quantities of good earth ______ each year.

A. is washing away          B. is being washed away

C. are washing away        D. are being washed away

它所给的答案是D. 此题中，earth 是不可数名词，但quantities 是复数，所以谓语采用了复数形式D.