一道英语试题Our factory is much more productive now.This year's production is five times ______ it was ten years ago.A.what B.that C.than D.as为什么选A

6.“...times+what+从句”.如：
The production is now three times what it was ten years ago.现在的产量比十年前增加了两倍.
因为production 后面than没有比较的对象啊,他和谁比?
所以,要么照这个句型做
要么..than what...出现比较的事物
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以下是总结
这里有倍数表示的详细说明
倍数表达法是高中英语教学的重点,也是历届高考的热点.当我们要表达甲是乙的几倍时,通常用下面三个句型来表示：
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”.如：
This rope is twice longer than that one.这根绳子是那根绳子的两倍长（比那根绳子长一倍）.
This hall is five times bigger than our classroom.这个大厅比我们的教室大四倍(是我们教室的五倍).
The car runs twice faster than that truck.这辆小车的速度比那辆卡车快一倍（是那辆卡车的两倍）.
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”.如：
Asia is four times as large as Europe.亚洲的面积是欧洲的四倍.
This big stone is three times as heavy as that one.这块大石头的重量是那块的三倍.
The plane flew ten times as high as the kite.那架飞机的飞行高度是那只风筝的十倍.
3.“A+倍数+the size/height/length/width,etc+of+B”,表示“A正好是B的多少倍”.如：
This street is four times the length of that one.这条街是那条街的四倍长.
This hill is four times the height of that small one.这座山的高度是那座小山的四倍.
除掌握倍数表达的三个常规句型外,我们更要注意的是其常规句型的变形及其特殊规律.
一.常规句型的变形
1.“ ...times+more+名词（可数或不可数）+than+被比对象”.如：
There are five times more books in our library than in yours.我们图书馆里的书比你们图书馆多四倍.
We have produced twice more grain this year than we did last year.我们今年生产的粮食是去年的两倍.
2.“ ...times as many/much+名词+as+被比对象”.如：
There is four times as much water in this pot as in that one.这个壶里装的水是那个壶里的四倍.
There are six times as many students as we expected.学生数量是我们预期的六倍.
3.“ ...times+over+被比对象”.如：
The grain output in that village is twice over that of 2002.那个村的粮食产量是2002年的两倍.
4.“ ...times+that+of+被比对象 ”.如：
In this workshop,the output of July was 4.5 times that of January.这个车间7月份的产量是1月份的4.5倍.
5.“...times+compared with+被比对象”.如：
The number of the students in our school has increased 4 times compared with 1980.我们学校的学生人数比1980年增加了三倍.
6.“...times+what+从句”.如：
The production is now three times what it was ten years ago.现在的产量比十年前增加了两倍.
二.倍数/百分数（percent）+compared with/up on +被比对象.如：
Our factory ' s output of TV sets in the first six months of this year was 10% up compared with last year.今年头六个月我们厂电视机的产量与去年相比增加了10%.
The industrial output of last year in our factory was 35% up on that of 2001.我们厂去年的工业产量比2001年增加了35%.
三.用double表示倍数
1.double用作形容词,表示“两倍的”.如：
The production is now double what it was ten years ago.现在的产量是十年前的两倍.
2.double用作动词,表示“是……的两倍.如：
The output has been doubled in the past six years.在过去六年中产量已经翻了一番.
This brought a steady rise in the grain yield.In 2002 it nearly doubled that of 1980.这使粮食产量不断增长,到2002年产量已经比1980年翻了一番.