21. For him ____ stage is just ___ means of making a living.
A. a; a B.the; a C. the ; the D. a; the
22. How did you find your visit to Qingdao, Joanna?
A. Oh, wonderful indeed B. I went the alone
C. First by train and then by ship D. A guide showed me the way
23. Engines are to machines ____ hearts are to animals.
A. as B. that C. what D. which
