Choose the appropriate pair of verbs to complete the sentence:- I did…

The correct answer is Option (2) → had seen, would have spoken

Third conditional:

• It imagines a past situation that did not happen, and its result, which did not happen either.
• Pattern:
  • If-clause: had + past participle.
  • Main clause: would have + past participle.
• This sentence:
  • "I did not see you at the party" is a fact about the past, and the second sentence imagines the opposite, so it needs the third conditional.
  • If-clause: had + seen → "If I had seen you".
  • Main clause: would have + spoken → "I surely would have spoken to you".
    Complete sentence: I did not see you at the party. If I had seen you, I surely would have spoken to you.

Why the Other Options are Incorrect?

Option 1: had saw, spoken — Incorrect.

• "Had" must be followed by the past participle seen, not the past tense "saw".
• "Spoken" alone, without would have, cannot be the main verb.

Option 3: seen, would speak — Incorrect.

• "If I seen" has no helping verb.
• "Would speak" belongs to the second conditional, which is for imagined present or future situations, not the past.
  Example: If I saw him now, I would speak to him.

Option 4: had see, would have speak — Incorrect. Both verbs are in the base form, but "had" and "would have" need the past participles seen and spoken.

Contrast: the third conditional (had + past participle, would have + past participle) imagines the past. The second conditional (would + base verb) imagines the present or future.