Reduced relative clauses: keep the meaning, remove the repeated subject

✂️ When can “students who are waiting” become “students waiting”?

A relative clause can often be shortened when its subject is the same noun it modifies. The reduced phrase must still show whether that noun performs or receives the action.

A full relative clause is shortened through active, passive and infinitive paths — Active meaning usually uses -ing; passive meaning usually uses a past participle.

Three common patterns

Active: The girl who is speaking → the girl speaking.
Passive: The books that were donated → the books donated.
Infinitive: the first runner who finished → the first runner to finish.

⚠️ Do not remove information needed for time or logic

People who had completed the course explicitly locates completion before another past event. A simple reduced form may blur that relationship. Reduction is an option, not a command.

🔎 Expansion test

Expand the phrase back into a full clause, identify its subject and voice, and confirm that the intended time and reference remain clear.