英语语法题Continuing costs for sports,on the other hand,are relat

英语语法题
Continuing costs for sports,on the other hand,are relatively low,requiring only a few part-time staff and maintenance routines
1.分析一下句子
2.为什么 require 是进行时,requiring 后面做什么成分

答：对我而言,句子的结构分析不是问题.问题在于continuning costs的理解.为弄清楚它的意思,我搜索网络,发现它摘自英语范文Should universities finance students’sports activities equally as libraries?中的一句话.
In addition to the costs of building adequate library facilities,a university must also pay every year to keep its collection well organized and up-to-date.The goal of every university library should be to have the most current books and materials its students need in order to study and do cutting edge research.The larger the students body,the more comprehensive a library’s collection must be.A well-trained staff must also care for materials and help the students.Continuing costs for sports,on the other hand,are relatively low,requiring only a few part-time staff and maintenance routines.For the most part,students are happy to organize their own sporting events and exercise routines quite independently of the school.
句子分析：
主语：Continuing costs for sports
谓语：are (系动词）
表语：relatively low
分词短语作状语,表示伴随情况、或补足说明：requiring only a few part-time staff and maintenance routines.
插入语,状语：on the other hand
结合前文,这个continuning,我想译作“后续的”.
译：另一方面,运动的后续开支相对是很低的,仅需要一些业余的工作人员用维护的工作.
注：V-ing是非谓语动词,不是谓语的进行时态.进行态需要助动词be+V-ing.
句子中的requiring.这个分词短语,肯定不是谓语,而是非谓语.
不是主语、不是宾语,也不是定语,也不是表语,也不是补语,只能是状语.
至于是什么状语,不同的人会有不同的理解.有说是原因状语的,相当于because 从句,说得通.
也有说结果状语的,是什么动作的结果?不通.
有说伴随状语的（我的说法）,补充成分.其实从我的汉语翻译来看,也看不出是什么状语,加上个“因为”,就是原因状语.所以有时候只需要说是状语就可以了.