5 His father is a doctor, .....?

The correct question tag is: ... isn't he? **Explanation:** The main clause is "His father is a doctor." Since the verb is in the affirmative form ("is"), the question tag needs to be in the negative form. The subject is "His father," which can be replaced by the pronoun "he." So, the correct question tag is "isn't he?" Complete sentence: His father is a doctor, isn't he?