问题补充：
Johnson bought a new car last week, and doubled that of the old one.
A. which price
B. the price of which
C. its price
D. the price of whose
答案：
A. which price
B. the price of which
(答案→)C. its price
D. the price of whose
解析：考查并列句.本句是由and连接的两个并列句,故不用引导词,下文特指上文汽车的价格,故用物主代词its,它的,选C.
