21．Keeping a diary is ____ good habit, by which you'll make ____ great progress in writing.
A．a; a B．a; 不填 C．the; a D．the; 不填
22．—Excuse me, is this shop open all day?
—____．It's only open from 9 a.m. to midnight．
A．Well, I'm not sure B．Oh, it's nothing special
C．Sorry, I'm afraid not D．Yes, of course not
