When _________ an egg for the first time, the hen lay in the doghouse.
Last term our maths teacher set so difficult an examination problem _____ none of us worked out.
How pleased the detective was _____ what his customer told him!
Mrs. Brown was much disappointed to see the washing machine she had _____ went wrong again.
-Has Tommy finished his homework yet?-I have no idea; he ____ it this morning.
-If you have time tonight,I’d like to invite you to a ball. -That’s very nice of you,but are you ____?