They asked me to have a dinner in an excellent restaurant with the, I said that it was at least five years since I _______ a good meal.

A．had enjoyed

B．was enjoying

C．enjoyed

D．had been enjoying

对某居室空气中氡的监测表明，其含量远高于室外空气，其最有可能的来源是

A．房屋地基及建筑材料
B．吸烟
C．人的呼出气
D．燃料的燃烧
E．家用电器