21． —Please sit down and have a break. You have been working on this machine
nonstop for two hours.
—No, thanks. .
A．I’m not in the least tired B．I’m too tired to move
C．I’m not a little tired D．I’m a bit tired
22．While income worry is _______ rather common problem of the aged, loneliness is another problem that ________ aged parents may face.。
A. a; 不填 B. the; 不填 C. a; the D. the; the
