Choose the most appropriate passive construction of the given sentenc…

The correct answer is Option (3) → The old man was heard by the neighbours to call for help late at night.

Passive of “hear + object + verb”:

Change	Active	Passive	Why
Object becomes subject	the old man	The old man	The old man is the one heard, so he becomes the subject.
Tense kept	heard	was heard	“Heard” is in the simple past, so the passive stays in the simple past: was / were + past participle (V3). “Was” because the old man is one person.
“To” added	call	to call	In the active, “call” comes without “to” after “heard the old man”. In the passive, “to” must come before it.
Agent (by ...)	The neighbours	by the neighbours	The neighbours are named, so the doer comes after “by”.
Full sentence	The neighbours heard the old man call for help late at night.	The old man was heard by the neighbours to call for help late at night.

“See” and “make” work the same way: saw + object + verb → was seen to + verb, made + object + verb → was made to + verb. Example: The guard saw a man climb the wall. → A man was seen to climb the wall by the guard.

Why the Other Options are Incorrect?

Option 1: The old man was heard by the neighbours call for help late at night. — Incorrect. The word “to” is missing before “call”. In the passive, “was heard” must be followed by “to + verb”.

Option 2: The neighbours were heard by the old man to call for help late at night. — Incorrect. This turns the meaning around. Now the old man hears the neighbours call for help.

Option 4: The old man is heard by the neighbours to call for help late at night. — Incorrect. “Is heard” is the simple present. The active “heard” is the simple past, so the passive needs “was heard”.