Passives and reduced relative clauses are two different grammatical structures used in English.

1. Passives: A passive construction is used when the subject of a sentence is the receiver of an action, rather than the doer of the action. In a passive sentence, the object of the active sentence becomes the subject, and the verb is changed to a passive form (usually with the auxiliary verb “be” + past participle). For example:

Active: The cat chased the mouse. Passive: The mouse was chased by the cat.

In the passive sentence, “the mouse” (the object of the active sentence) becomes the subject, and the verb “chased” is changed to “was chased” (passive form).

1. Reduced relative clauses: A relative clause is a type of dependent clause that provides additional information about a noun in the main clause. A reduced relative clause is a shortened form of a relative clause, where the relative pronoun and the verb “be” are omitted. For example:

Full relative clause: The book that is on the table is mine. Reduced relative clause: The book on the table is mine.

In the reduced relative clause, the relative pronoun “that” and the verb “is” are omitted, resulting in a shorter and more concise sentence.

It’s important to note that reduced relative clauses are only possible when the relative pronoun is the object of the relative clause and can be omitted. If the relative pronoun is the subject of the relative clause, it cannot be omitted, and a full relative clause must be used.