求问一个考研英语的长句.

题目

求问一个考研英语的长句.
It matters that because theory suggests that maximum sustainable yield that can be cropped from a fishery comes then the biomass of a target species is about 50% of its original levels.有两点困扰的,一个是 come到底是修饰什么的?如果是yield,那么crop修饰的又是什么?还有就是level为什么要带s?

答案

你这个句子写的不对啊,网上的原文是这样的：That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about ...