He knows it is high time that he ________ at once.

-- It’s many years since I saw you last； I _____ you at all.--- I wouldn’t have, either, if someone ______ you by the name.

______ smoking, he would not have got cancer in the lung.

____you had worked hard, you would have easily passed the final test.

You can’t imagine that a well –behaved gentleman ______ be so rude to a lady.