1. The voice of the verb is distinct from its tense. Don't confuse the passive voice with the past tense. (Sentence 2 happens to be in the past tense, but 3 is not; both 2 and 3 are in the passive ...

Often, in language use, deciding whether to use the present perfect or the past simple depends on your ... so I choose to use the present perfect passive tense. Similarly, twenty people were ...

Use your current topic — that is, what you are writing about — as the grammatical subject of your sentence (see Verbs: Choosing between active and passive voice). When writing a complex ...