Lesson 1: Tenses and Their Aspects, section B, lists 'It has been raining for two hours' as an example, and Lesson 5: Present Perfect Continuous Tense, section A, explains that sentences referring to an incomplete action which started in the past but is still going on (like 'I have been watching it for about an hour' and 'It has been raining since 7 o'clock') are examples of the present perfect continuous tense.
Class 6 › English Grammar and Composition › Chapter 2: The Tenses › Topic: The Present Tense
Aligned to the NCTB national curriculum.