Reduce Clauses to Phrases
A. REDUCED RELATIVE CLAUSES:
I. The verb of the relative clause is Be : Delete the subject and Be (no matter which tense is used).
Ex: The man who is/was/has been in the front row is my father. → The man who is/wasin the front row is my father. (relative → adverbial)
Mr Benson, who is a famous scientist, is my father. → Mr Benson, a famous scientist, is my father. (relative → appositive noun phrase)
But : The man that is/was/has been there is my father. → The man there is my father. (There is an adverb in the relative clause)

2. The verb of the clause isanordinary verb : The most important thing is to get to know whether the verb is ACTIVE or PASSIVE.
2.1. Delete the subjective relative pronoun and transform the verb into participle (no matter which tense is used).
*The verb is active : →Present participle (ing form) or perfect participle (having+past participle, ex: having done, having behaved)
Ex: The man who wants to talk to you is my father. → The man wanting to talk to you is my father.
The man who had shouted at my father said sorry. → The man having shouted at my father said sorry.
The man who has grey hair is my father. → The man having grey hair is my father.
→ The man with grey hair is my father.
The man who is wearing a blue suit is my father. → The man wearing a blue suit is my father.
→ The man in a blue suit is my father.
Give this to anyone who comes first! → Give this to anyone coming first.
The man who has been running since 6 o’clock is my father.→ The man (having been) running since 6 o’clock is my father.
* The verb is passive: →Past participle (ed form)
Ex: The man who is wanted (by the police) is my father.→ The man wanted (by the police) is my father.
The man who was given a big award is my father. → The man given a big award is my father.
The man who has just been bitten by your dog is my father. → The man just bitten by your dog is my father.
2.2. Omit the objective relative pronoun in the restrictive relative clause (not the the non-restrictive relative clause)
Ex: The man that/whom you saw yesterday is my father. → The man you saw yesterday is my father.
The man that/who you talked to yesterday is my father.→ The man you talked to yesterday is my father. (informal style)
The dog that/which you saw yesterday is my father’s. → The dog you saw yesterday is my father’s.
BUT: The man to whom you talked yesterday is my father.→ The man to you talked yesterday is my father.
(NOT POSSIBLE : formal style: relative pronoun next to a preposititon)
The sofa in which you are sitting is my father’s. → (NOT POSSIBLE, relative pronoun next to a preposititon)
3.Not possible:
3.1. The relative clause hasan adjective (after Be):
Ex: The man who is angry is my father. → The man angry is my father.
But : →The angry man is my father. (Possible with placing the adjective before the noun)
3.2. The relative clause has a noun (after Be):
Ex: The man who is a doctor is my father. → The man a doctor is my father. (Not possible with a restrictive relative)
But : Mr Benson, who is a doctor, is my father. → Mr Benson, a doctor, is my father. (Possible with a non-restrictive relative)
3.3. The relative clause has a modal:
Ex: The man who can swim is my father → The man can swim is my father.
3.4. With theemphatic form : IT/THAT + BE ....
Ex: That is the man who was in prison last year. →That is the man in prison last year.
Those are the boys that have broken the window. → Those are the boys breaking/(having broken) the window.
It was my fatherwho invented the nuclear weapon. → It was him inventing the non-explosive match.
3.5. With a few verbs not having ing-forms:
Ex. The man who likes horror movies is my father. → The man liking horror movies is my father.
3.6.The sentence has an adverb which may causes ambiguity or misunderstanding :
Ex: He has married