a large amount of 和 large amounts of的区别：
1.a large amount of +不可数名词，谓语动词用单数；
例：A large amount of money was spent on the bridge.
在这座桥上花了大量资金。
2.large amounts of+ 不可数名词， 谓语动词用复数。
例：Large amounts of money were spent on the bridge.
在这座桥上花了大量资金。
3.偶尔也可见到其后接复数可数名词的用法，但不算普通。如：
The shopkeeper had a large amount of oranges in his storeroom. 店主在货仓里存有大量橙子。——摘自《朗文当代高级英语词典》 Even small amounts of these substances are known to cause skin problems. 我们知道这种物质即使是一丁点也会损害皮肤。——摘自《剑桥高阶英词典》