I have asked this question before but I'm still confused. I want to know that after reading a story, if a comprehension question is asked in the present or past tense, are we bound to answer it in present or past tense respectively. I would be grateful if anyone can answer me with examples in detail.

The answer is usually in the same tense.
Q - Does Tom marry Mary?
A - Yes, he does.

Thnak you so much Clive.