decrease by 和to区别

意思不一样：decrease by意思是“减少了”，而decrease to意思是“减少到”。decrease by a%意思是减少了百分之a；而decrease to a%的意思是减少到百分之a。两者都有下降的意思。

例句

It predicts the number of people living on less than$2 a day will decrease by 24 million this year.

它预测，每天生活费低于两美元的穷困者人数今年将减少2400万。

Study on anatomy,ct image and clinic of bleeding decrease by ligaturing the internal vertebral venous trunk

结扎椎管内静脉干减少腰间盘切除术出血的解剖学、CT影像及临床研究。

Try to decrease to two servings of salad dressing,cooking oil,butter,and mayonnaise。

尽量将油脂用量减少至两餐分量，这里面包括沙拉调味料、食用油以及蛋黄酱所含的油脂分量。

Did it more than double,did it remain about the same in the world as a whole,or did it decrease to less than half？

是翻倍了还是在全世界范围内总体不变，还是下降了一半呢。