Question

Change the sentence “ He could buy many books on discount ” into an interrogative sentence

• A. Could he buy many books on discount?
• B. Can he buy many books on discount?
• C. Will he buy many books on discount?
• D. Did he buy many books on discount?

Hint:

If a declarative sentence contains a modal verb (can, could, will, would, shall, should, may, might, must), simply invert that exact modal verb with the subject to construct the interrogative version. Never substitute the modal verb for another!

Answer 1

The Correct Option is A

Concept: Just like the previous problem, transforming an assertive sentence containing a modal auxiliary verb into an interrogative structure demands strict adherence to the inversion rule without altering the original modal auxiliary or the tense. Let us review the anatomy of the original statement:
• Original Sentence: "He could buy many books on discount."
• Modal Verb identified: The word "could" is a modal auxiliary verb indicating past capability or possibility. To transform this into a question, the modal auxiliary verb "could" must be brought to the absolute front of the sentence, preceding the subject "He", while the base form of the main verb ("buy") remains unchanged: \[ \text{Subject (He)} + \text{Modal (could)} + \text{Base Verb (buy)} \quad \Rightarrow \quad \text{Modal (could)} + \text{Subject (He)} + \text{Base Verb (buy)}? \] Applying this gives us: "Could he buy many books on discount?" Let us look at why the other options fail:
• Option (B) Can... shifts the modal to the present capability form "can", altering the original past perspective.
• Option (C) Will... changes the aspect completely to a future intent or prediction using "will".
• Option (D) Did... completely removes the modal element of "capability/possibility" and turns it into a generic inquiry about a completed past action. Therefore, Option (A) is the only accurate choice.