问题补充：
This year they have produced they produced the year before last.
A. twice many cars as
B. twice as many cars as
C. twice more than cars
D. twice the cars of
答案：
A. twice many cars as
(答案→)B. twice as many cars as
C. twice more than cars
D. twice the cars of
解析：考查倍数。倍数的表达有：倍数 + as + 形容词或副词的原级 + as + 其他；倍数 + 形容词（或副词）的比较级 + than + 其他；倍数 + the size / height / length / width. etc. + of + 其他。故选B。
