21.The Labor Day holiday encouraged many people to take ______ public transportation, with all of _____ subway’s lines in Beijing breaking passenger records on Saturday.

A./; /                 B. the; the              C. /; the           D. a; the

22. Recently I bought an ancient Chinese vase, _____ was very reasonable.

   A. which price¡¡¡¡ B. the price of which¡¡¡¡C. its price¡¡¡¡    D. the price of whose

23. Last week, only two people came to look at the house, ____wanted to buy it.

 A. none of them    B. both of them                        C. none of whom  D. neither of whom