Present perfect continuous and past perfect continuous

Question

What's the difference between:

1. [...] who have been dominating the sport for a couple of years.

2. [...] who has been dominating the sport for a couple of years

3. [...] who had been dominating the sport for a couple of years.

My main problem here is when to use has, have and had.

Answer 1

• Have/has been doing are both present perfect continuous forms and they only differ in the number of people you're talking about through the relative pronoun who:

  • My school teammate [singular], who has been dominating...
  • My school teammates [plural], who have been dominating.

  The present perfect continuous is used to talk about something that started in the past but whose effects are still visible.

• Had been doing is a past perfect continuous form, which is used to talk about something that started in the past and continued to have influence on the events that occurred up until another time in the past. Since there's no difference in the singular and plural forms of the English verbs used at a past tense, you can use who had been doing both to talk about a singular subject and to refer to a plural one:

  • My school teammate [singular], who had been dominating...
  • My school teammates [plural], who had been dominating...
    

  and the number of people used as a subject can be deduced from the noun who is referring to.

You may find useful this timeline
_{(source: englishlessonsbrighton.co.uk)}

the shadowed area for the present perfect continuous and the past perfect continuous tenses indicates that those forms are used to talk about an event that has a (finite) duration up until the present moment (for the former) or a moment in the past (for the latter).