If I had worked hard, I … very high marks in the exam.

Step 1: Analyze the question

The sentence is "If I had worked hard, I ___ very high marks in the exam." The "if" clause uses the past perfect ("had worked"), which signals a particular kind of conditional sentence.

Step 2: The concept: the Third Conditional

The third conditional talks about an unreal situation in the past, something that did not happen, and its imagined result.

Structure:

• If + past perfect (had + past participle), would/could/might + have + past participle

Examples:

• If she had studied, she would have passed.
• If we had left early, we would have caught the bus.

Step 3: Apply it to the sentence

• The "if" clause: had worked, which is past perfect. ✔
• The main clause needs: would have + past participle
• The past participle of "score" is scored.
• So the main clause is: would have scored

Step 4: Check each option

• A. would have score: Wrong. After "have" we need the past participle (scored), not the base form.
• B. will score: Wrong. This is future tense and does not match a past unreal condition.
• C. would have scored: Correct. It follows the third conditional pattern exactly.
• D. can score: Wrong. This is present tense and does not fit the past condition.

Complete sentence: "If I had worked hard, I would have scored very high marks in the exam."

Correct answer: C

💡 Exam Tip: When you see "If + had + past participle", look for "would have + past participle" in the options. Eliminate any option with a base verb after "have" (like "would have score") or with a present or future form (will, can). Conditionals appear often in JAMB English, so memorise the three patterns:

1. If + present, will + verb (real/possible)
2. If + past, would + verb (unlikely/imaginary)
3. If + had + past participle, would have + past participle (impossible, past)

You've got this! 💪