a quantity of+可數(shù)名詞復(fù)數(shù)、謂語動詞用復(fù)數(shù)；a quantity of+不可數(shù)名詞、謂語動詞用單數(shù)。即修飾可數(shù)或不可數(shù)名詞均可，作主語時采取就近一致的原則，其謂語動詞通常與短語中of后面的名詞的數(shù)保持一致。

a quantity of謂語用單數(shù)還是復(fù)數(shù)

a quantity of+可數(shù)名詞復(fù)數(shù)、謂語動詞用復(fù)數(shù)；a quantity of+不可數(shù)名詞、謂語動詞用單數(shù)。

若單獨用quantity作主語，謂語動詞用單數(shù)。

如：It is used to emphasize that the quantity is very large。

它用于強調(diào)數(shù)量很大。若該結(jié)構(gòu)變成(large)quantities of…這樣的形式，則當(dāng)它用作主語時，其謂語動詞一律用復(fù)數(shù)。

如：Huge quantities of oil were spilling into the sea。大量的石油滲到海里。

quantities of和a quantity of的區(qū)別

quantities of和a quantity of都可以修飾可數(shù)名詞和不可數(shù)名詞，區(qū)別在于：

quantities of在修飾不可數(shù)名詞，并且和后面的名詞一起做主語時，謂語由它決定，也就是用復(fù)數(shù)。

a quantity of修飾不可數(shù)名詞，并且和名詞一起做主語時，謂語動詞由后面的名詞決定，也就是用單數(shù)。

例如：Quantities of energy are saved today. (今天大量的能源被節(jié)約)

A quantities of energy are saved today.

Quantities of cash have been withdrawn from the bank.

(大量的現(xiàn)金已經(jīng)被從銀行取出)

Aquantity of ready-use 35 mm ammunition in clips is also carried.

一批準(zhǔn)備使用35毫米彈藥在剪輯，也獲得通過。

其他時候倆者可互換。

The milk carton, in turn, has a quantity of milk inside it.

=The milk carton, in turn, has quantities? of milk inside it

這盒牛奶，再進一步，它里面牛奶有一個量。