Had I hurried, I        the tram.

John promised his doctor he ________ not smoke, and he has smoked ever since.

 Had Yeats stopped writing at age 40, probably he ______valued as a minor poet now.

I should not have laughed if I________you were serious.               

—Your boss looks rather a kind person. —But in fact he is cold and hard on us. You ______ believe it!