What would have happened if__________?

সঠিক উত্তর: the bridge had been broken।

পূর্ণ বাক্য: What would have happened if the bridge had been broken?

3rd Conditional: If + Past Perfect Tense, would have/could have + Past Participle।

Bridge নিজে ভাঙতে পারে না, তাই বাক্যটি passive হবে। সেজন্য if-clause হবে If + had been + Past Participle।

Example: If you had come, I would have gone there.