IIMKGrammar > Mediumhad knownknowknewhave known✅ Correct Option: 1Related questions:He speaks as if he ______ the theory himself, though he barely understands it.In the following sentences, the incorrect part of the sentence is underlined. Choose an alternative from the four given options so that the sentence is rendered correct. If I had known that you needed to go to the airport yesterday, I could drive you there.Had it not been for her quick thinking, the plan ____ into chaos.