Of all the economically important plants, palms have been the least studied.

题目

Of all the economically important plants, palms have been the least studied.
of前面省略了什么

答案

没省什么!
of 在这里标范围”在.之中“
再如：
Of all the cities in China, Shanghai is the biggest.
在中国的所有城市之中,上海市是最大的.
O(∩_∩)O 认同请采纳,不懂继续问. 祝学习进步! 谢谢!