has not been是什么时态

has not been是现在完成时态。

现在完成时的构成是have/has＋动词过去分词。主语是第三人称单数时用has，剩下的用have. 例如 

l have had(have的过去分词)my lunch(我已经吃了午饭了).

He  has been a worker for a year(他当工人一年了).

现在完成时的否定式是在have/has后加not，例如

She has not  been(be的过去分词)a nurse for two months(她已经不做护士两个月了).