This post explains the use of the passive in the past, present, and the future. I'll explain when to use and why. We often use the passive in formal writing to sound impersonal.
This post explains the use of relative clauses /pronouns and how they link sentences. Explanations are also in pdf along with an exercise in a quiz and pdf formats.
Use the present perfect to talk about recent events or a past event which the speaker feels s is connected with
the present. Use the past simple to talk about a finished action.
Certain n time expressions may be used with the past simple.