When I dropped in, Dr Smith _____, so we only had time for a few words.

Have you seen ____Audi car I parked here?—Is it _____ black one? A young man has driven it away.

Do you know man in blue? —Yes, he is a professor of Jiangsu University.

．—How is your English going? — .

I found a boy _________ in the corner of the street on my way to the supermarket.