The traffic accidents in the city decreased by 30% last year.

题目

The traffic accidents in the city decreased by 30% last year.
The traffic accidents in the city decreased 30% last year.两句都对么?意思一样么?

答案

第一句是对的,介词by表示“减少了.”不可缺.介词to表示“减少到.”
第二句是错误的.