For Past Perfect Continuous, see here.
Hello! i have difficulties in understanding perfect tenses and differences between perfect continious tenses. Can you give the definite differences.thank you very much!
To understand the application of perfect continuous tense, you must be clear about the difference between continuous and perfect continuous.
Present Continuous tense expresses an activity happening at the moment of speaking. It never indicates the duration activity.
CORRECT: I am running now.
CORRECT : She is sleeping now.
INCORRECT: I am running for 2 hours.
INCORRECT: She is sleeping since 8:00 o’clock
On the other hand, Present perfect Continuous tense expresses an activity with duration. So the above incorrect sentences become correct if we use the perfect continuous:
CORRECT: I have been running for 2 hours.
CORRECT: She has been sleeping since 8:00 o’clock
Past Continuous vs. Past Perfect Continuous
If you do not include a duration such as "for five minutes," "for two weeks" or "since Friday," many English speakers choose to use the Past Continuous rather than the Past Perfect Continuous. Past Continuous emphasizes interrupted actions, whereas Past Perfect Continuous emphasizes a duration of time before something in the past. Study the examples below to understand the difference.
· He was tired because he was exercising so hard.
This sentence emphasizes that he was tired because he was exercising at that exact moment.
· He was tired because he had been exercising so hard.
This sentence emphasizes that he was tired because he had been exercising over a period of time. It is possible that he was still exercising at that moment OR that he had just finished.
We also use the Past Perfect Continuous to show that something started in the past and continued up until another time in the past. "For five minutes" and "for two weeks" are both durations which can be used with the Past Perfect Continuous. Examples:
· They had been talking for over an hour before Tony arrived.
· She had been working at that company for three years when it went out of business.