例句:
He ventured large sums of money on speculative stocks and was successful.
He quickly accumulated a large amount of assets in this way.
为什么sums of后接名词money,不需要用复数 ? (a sum of 和 sums of是一样的?)a amount of后面为什么需要跟复数assets呢 (amount不是应该跟不可数名词吗?)