It always takes the third person singular form of the verb even though it's always plural in English.

它总是使用动词第三人称单数的形式，尽管在英语中它的动词总是复数。

The noun "action" is singular; it is the singular form of "actions".

名词“ action ”是单数，他是“ actions ”的单数形式。

The noun "datum" is singular; it's the singular form of "data".

名词datum是单数，它是data一词的单数形式。

This noun appears in the singular form, never in the plural form.

这个单词只有单数形式，没有复数形式。

Though it appears in the singular form, it takes a plural predicate verb.

虽然形式上是单数，它必须跟复数的谓语动词。