Identify the tense used in the sentence "I have been reading this book for a week."

The tense used in the sentence "I have been reading this book for a week" is indeed the Present Perfect Continuous. This tense is employed to indicate an ongoing action that started in the past and is still in progress at the time of speaking or has recently stopped, but has relevance to the present moment.

In this case, "have been reading" highlights that the action of reading began a week ago and continues up to now, or it has just concluded but still holds significance. The use of "for a week" emphasizes the duration of this ongoing action, which is a key characteristic of the Present Perfect Continuous tense.

This tense is particularly notable for combining the auxiliary verb "have" with "been" (the past participle of "be") and the present participle "reading," which helps convey the continuity of the action over a specified timeframe.