对的,我也想说drop那个,我查了曼哈顿SC、prep08语法笔记、CD大神语法笔记,都没有drop后面有数字或百分比(表示下降了多少)的。
有道词典可以查到例句说drop by 50 per cent。
其他表“减少”的词也是+ by + x% (e.g. reduce by 10%,decrease by 10%)
所以我也觉得应该是有by的
The thickness of a certain material is very important for archeologist because the material compose/ consist of/ constitute the evidence of xxx 求助这三个词有啥区别?