participles are used as in the past tense.
In English, the past tense is in one of three ways: perfect, imperfect or pluperfect.
Imperfect past tense is simple and consists of only a pronoun or noun and the verb, such as:
he had they ran I did you were going.
These are not past participles, but imperfect conjugations of the . ‘You were going’ is interesting, because instead of using the imperfect conjugation of ‘to go’ (went), it conjugates ‘to be’ (were) and adds the gerund of ‘to go’ (going) onto the end. A gerund is a verb that can be used as a noun (e.g. ‘I love going to bed’) and normally ends in ‘-ing’.
The perfect past tense is where past participles are used. Perfect past uses a pronoun or noun, an auxiliary verb and a past participle. Auxiliary comes from Latin auxilium, meaning help.
I have gone she has watched you have been the writer has written.
Each of these uses a pronoun or noun (I, she, you, the writer), an auxiliary verb (have, has, have, has), and the past participle (gone, watched, been, written).
You can see that the past participle is different to the imperfect conjugation in the verb ‘to be’.
Imperf: ‘I was’, ‘you were’ Perf: ‘I have been’, ‘you have been’
The past participle is the form of the verb used after the auxiliary rather than just on its own.
Pluperfect is a combination of the two, using the imperfect conjugation as the auxiliary verb, such as
I had been we had played.
In the examples above, ‘I have been working for months’ and ‘it has been fixed’, there are two major differences, the first of which is the most important.
‘I have been working for months’ is active, because it is the subject of the sentence that has been working, while ‘it has been fixed’ is in the passive, since ‘it’ hasn’t actually done anything, merely been the object of the fixing.
Additionally ‘I have been working for months’ uses the gerundive to indicate ‘working’ is a continuous action, i.e. is still going on, whereas ‘it has been fixed’ does not. If it did, it would probably be ‘it has been being fixed’.