单选题 The output of television sets has ______ in the past five years.
A. more than doubled B. more than double
C. as many as double D. as much as double

【正确答案】 A

【答案解析】[解析] 这里的double是不及物动词，表示“增加一倍”或“是原来的两倍”。has doubled“已增加了一倍”；has more than doubled“已增加了一倍多”。double还可以用作及物动词，如：I shall double your wages；还可用作形容词，如：I shall give you double pay；还可用作名词，如：She offered me double for it.