Let's understand how to convert a statement with a modal verb into a question step-by-step:
Step 1: Identify the sentence structure
The sentence is:
He could count the number of persons in the crowd.
- Subject: He
- Modal verb: could
- Main verb: count
Step 2: Forming questions with modal verbs
For modal verbs like can, could, will, shall, may, etc., the question is formed by inverting the subject and the modal verb.
- Statement: He could count...
- Question: Could he count...?
Step 3: Keep the rest of the sentence unchanged
The rest of the sentence remains the same: the number of persons in the crowd.
Step 4: Putting it all together
The correct interrogative sentence is:
Could he count the number of persons in the crowd?
Why not the other options?
- Option (A) "Who could count..." changes the meaning by turning it into a question about the person, not a yes/no question about ability.
- Option (B) "Anyone could count..." is not a question, but a statement.
- Option (D) "Can he count..." uses present tense "can" instead of past tense "could," so it does not match the original sentence tense.