Hi.
Please tell me if a past or present perfect or both is possible if we have these underllined phrases.
He was/has been a sales person for the last two years/during the previous two years/for two years. -- for these, I think both past and past perfent tenses are allowed.
He has been a sales person in the past two years/for the past two years. -- I think, for these, no past tense is allowed.