今年产量比去年增加两倍。
=今年产量是去年的三倍。
估计这个表达至今还在坑学生。你能分清吗？
而且还能接着坑英语。看这个练习——
“今年产量比去年同期增长两倍。”
到底说increase by twice？还是by three times？还是to three times？
有人这么解释：
略作考证——看看by的相关解释
剑桥词典的解释
We use by to talk about measurements, and increases and decreases in amounts:
The price of fuel has increasedby12% this year.
油价今年上涨了12%。
https://dictionary.cambridge.org/grammar/british-grammar/by
麦克米兰词典的解释
used for showing how much something has changed, or how much difference there is between things
House prices rosebyan average 23%last year.
去年房价平均上涨了23%。
Owen broke the world record by 2.4 seconds.
欧文打破世界纪录，将时间又缩短/延长了2.4秒。
http://www.macmillandictionary.com/dictionary/british/by
朗文词典的解释
Used to show the amount or degree of something 数量【程度】达到……
The price of oil fell by a f urther $2a barrel.
每桶油价又下跌了2美元。
I was overchargedby $3.
他们多收了我3美元。
再找找authentic的例子
新加坡《海峡时报（英文版）》一则新闻标题：
SingaporeBudget 2017: Water prices toincrease by 30% from July 1 in two phases
BY后面就是增加出来的量。也就是说：增加后的数量减去增加前的数量，就是BY后面的数量——对不对？
谁这么说过increase by twice的话啊。
我表示怀疑：这又是一粒本土英语的产物。
China Daily的报导
China's real estate prices maintained their robust growth in October. The sales prices of high-end and ordinary residential buildings sawyear-on-year risesof7.7 per cent and 6.4 per cent, up 0.7 and 0.1 percentage points compared to last month.
“据报道，10月份，全国70个大中城市新建商品住房销售价格同比上涨6.4%，涨幅比上月提高0.1个百分点；高档住房销售价格同比上涨7.7%，涨幅比上月提高0.7个百分点。”
可见“同比”可用“year-on-year”来表达，指“与上年同期数字相比的”。“同期增长”则为“year-on-year rise”或“year-on-year growth”。
可见，关于这个表达，常见的、正确的、地道的说法，不外乎三种：
1、直接用double、triple这样的动词：
The production has tripled.
2、直接用increase+倍数
A has increased three times
就是A乘以三。与我们纠结的A has increased by three times一样，都是指A增加了两倍。（貌似只有我们学过小学数学的人才会纠结是不是要说A has increased by three times。老外算数不好，分不清，所以这种表达本身就不是很清楚。）
3、用名词year-on-year increase/rise of （数值）
如上新闻的例子。
黔无驴，有好事者船载以入。——英语本无此纠结问题，有好事者，非要把这个“增加了、增加到”夹带到英语中，原本是为了让学生理解by的用法。为考试英语而复杂化，结果得不偿失啊。返回搜狐，查看更多