Look at the mess the boys made! You _______ have taught them how to behave themselves.

       for the free tickets,I would not have gone to the film so often.

 "You know so much about literature. It's a pity you failed your degree," Harry said, "You ______ a good teacher."

Although this ____ sound like a simple task, great care is needed.

— Did you go to the lecture by the visiting professor?— No. I ______ it, but I've been busy taking care of my grandma in hospital these days.