Select the option that expresses the given sentence in passive voice. Historians tell us how this country was divided into three.

Correct — C. Only the main clause converts. The sentence carries two verbs: tell in the main clause and was divided in the noun clause that follows how.

Historians tell us → the object us becomes the subject we, tell becomes are told, and the old subject follows as by historians. The tense stays simple present.

The clause how this country was divided into three is already passive, and it is reported material rather than the verb being converted, so it is copied across untouched.

Simple present passive plus an unchanged noun clause is option (c).

Why the others are wrong

• (a)
  We have been told by historians how this country was divided into three. — have been told is present perfect, but the verb being converted is the simple present tell. Shifting the tense of the main verb is the commonest way these options are spoiled.
• (b)
  We are told by historians how this country divided into three. — It deletes was, leaving this country divided into three, which now reads as active and says the country did the dividing. The reported clause must be reproduced as it stands.
• (d)
  We are told by historians how this country has been divided into three. — has been divided moves the noun clause from past simple passive to present perfect passive. That clause was not the one to convert, so its tense may not be shifted either.

Voice conversion changes one verb — the finite verb of the clause you are told to convert. A subordinate clause hanging off it travels unchanged.

The drill for the main clause is fixed. The object becomes the subject, the verb becomes the matching form of be plus the past participle, and the old subject follows by.

Here that gives us → we, tell → are told, historians → by historians. The tense is preserved and never upgraded.

Key facts

• Simple present passive is am, is or are plus the past participle, so tell becomes are told.
• A subordinate clause introduced by how, that or why is reported material and keeps its original tense.
• Verbs of telling take two objects, so the person object can become the passive subject.

Common traps

• Converting the subordinate verb as well, which yields this country divided or has been divided.
• Upgrading the main verb to present perfect because the sentence sounds like a report.

No directly related past PYQ was found.