[ Grammar ] How to reduce a perfect-tensed relative clause? I am trying to figure out how to reduce a relative clause when it is made up of a ( present / past ) perfect tense in active and passive voice. S1: ( present perfect tense in active voice ) The house that has collapsed will be rebuilt in two years. Reduced forms: S2: The house having collapsed will be rebuilt in two years. S3: The house collapsed will be rebuilt in two years. S4:The house collapsing will be rebuilt in two years. ---- Q1: S2~S4, which one is the reduced form of S1 ? Q2: How to return S2~S4 back to the form which is not reduced? Q3: Is it suitable to reduce a relative clause S1? ---- T1: ( past perfect tense in passive voice ) the picture that/which had been torn into pieces….. Reduced forms: T2: the picture having been torn into pieces… T3: the picture torn into pieces… T4: the picture being torn into pieces… ---- Q4: T2~T4, which one is the reduced form of T1 ? Q5: How to return T2~T4 back to the form which is not reduced? Q6: Is it suitable to reduce a relative clause T1? Q7: How to know when is suitable to reduce perfect-tensed relative clauses? ---- Thanks a lot : )