What are the uses of the present perfect continuous tense?

The present perfect continuous tense is used to describe an action that started in the past, is still ongoing in the present, and is expected to continue into the future. It is formed by using the auxiliary verb "have" in the present perfect tense, followed by "been" and the present participle form of the main verb (-ing form).

1. Ongoing actions: The present perfect continuous tense is used to describe actions that started in the past and are still happening at the time of speaking. For example: "I have been studying for three hours." This implies that the person started studying in the past and is still studying at the present moment.

2. Duration of an action: This tense is used to emphasize the duration of an action that started in the past and is still ongoing. For example: "She has been working on this project for months." This indicates that the person started working on the project in the past and is still working on it in the present.

3. Temporary situations: The present perfect continuous tense can be used to describe temporary situations or states that started in the past and are still continuing. For example: "They have been living in London since last year." This suggests that the individuals started living in London in the past and are still living there presently.

4. Repetition of actions: This tense can also be used to describe actions that have been repeated over a period of time leading up to the present moment. For example: "He has been playing the piano since he was a child." This implies that the person started playing the piano in the past and has continued to play it repeatedly until now.

5. Annoyance or irritation: The present perfect continuous tense can be used to express annoyance or irritation about an action that has been happening for a long time. For example: "She has been talking on the phone for hours!" This suggests that the person has been talking on the phone for a long time, and it is causing annoyance or irritation.

It is important to note that the present perfect continuous tense focuses on the duration or ongoing nature of an action rather than its completion.