After the new technique was introduced，the factory produced in 2001 as the year before．A.

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(答案→)A. as twice many machines
B. twice many as machines
C. as many machines twice
D. twice as many machines
解析：考查倍数表达。倍数表达的基本结构：
1. “A+倍数+形容词或副词的比较级+than+B”，表示“A比B大（长、高、宽等）多少倍”。
2.“A+倍数+as+形容词或副词的原级+as+B”，表示“A正好是B的多少倍”。
3. “A+倍数+the size/height/length/width， etc+of+B”，表示“A正好是B的多少倍”。
4. “……times+what+从句”。
可知选项BCD结构错误，故选A。