21．The WTO can't be called _____ "world" organization without ____ world’s largest nation-Russia．
A．the; a B．a; a C．the; the D．a; the
22．—I got promoted a few days ago．
—You did? _____!
A．Thank you B．Never mind C．Congratulations D．Don't worry
23．If our time is usefully employed, it will _____ some useful and important products．
A．turn out B．refer to C．look up D．carry on
