quantity

n.①[U]量  ②数目，数量

【用法】  quantity of后面可接不可数名词或可数名词的复数，作主语时，谓语动词的形式由quantity的单复数形式决定，而与其后面的名词无关，如：

Large quantities of water have beenpolluted now./A large quantity of appleshas been sent to children.