Do you have any idea ______ on earth has happened to our friend?
Do you know _______ man in jeans?—Yes. He’s a professor of _______ university.
Are Mr. and Mrs. Wang living alone in the house? —-Yes, altough they have three sons, of them live with their parents.
How long has your grandpa ______?-For about 3 months.
You can never imagine what great difficulty I have ________ your house.