I. 选择填空（Multiple-choice）（共15小题；每小题1分，计15分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。(Beneath each of the following sentences there are four choices marked A, B, C and D. Choose the answer that best completes the sentence.)
31. Alice is fond of playing ________ piano while Harry is interested in listening to ________ music.
A. /; the        B. /; a     C. the; /       D. the; a