Part F. The Present Perfect Continuous Tense
- The present perfect continuous describes continuous actions that started in the past and have continued on to the present. They often continue into the future (unfinished actions). Again, for or since are often used with this tense to show the length of time.
If the action is not finished, it is described as the unfinished past.
I have worked here for three years.
She has been teaching here since 2004.
Present result is used to show how the past activity has a present result or consequence.
She has been studying all night. She is tired.
He has been taking exams. He is stressed.
Present Perfect vs. Present Perfect Continuous
Since both perfect forms can express unfinished past, there are some verbs that can be used with both tenses, with little difference in meaning.
I have worked here for ten years.
I have been working here for 10 years.
The only difference is that, like all continuous forms, the second sentence gives a sense of being temporary. (some people would say that they have worked sentence focuses on how long and the other sentence focuses on the action) This is not a big difference. In practical usage, either form is acceptable. The important use of unfinished past with the simple form is to show duration.