虽然action既能作可数名词也可作不可数名词，但在take action词组中action 为不可数名词，所以该词组通常不说take actions。例如：

《麦克米伦高阶英汉双解词典》

action 【U】the process of doing something, especially in order to stop a bad situation from developing or continuing (尤指制止坏的局面发展或继续的)行动过程

take action (=begin to do something to solve a particular problem) 采取行动

We urge the authorities to take action. 我们敦促当局采取行动。

《简明英汉词典》

The police had to take firm action to deal with the riots.

警方不得不采取果断行动来对付骚乱。

《牛津英语搭配词典》

Disciplinary action will be taken against students who cheat.

对作弊的学生将予以惩戒。