21. — Why not go and have dinner in a restaurant?
— ______ It’s too expensive.
A. Why not? B. I agree. C. I’m afraid not. D. I’m sure.
22.—Have you seen _____ new bike? I put it here just now.
—Is it ______white one? A boy has ridden it away.
A．a ; a B．a; the C．the; the D．the; a
