然而,这必须和城市儿童能得到的好处相权衡,我们对这些儿童有最大的照拂他们的责任.
However,this must be weighed against the benifits for city children （for whom we all have he geatest duty of care）.括号前的是主句,括号里的是修饰city children的从句.
这句话分成两句,However,this must be weighed against the benifits for city children.We all have he geatest duty of care for them.for whom是从for them来的,这是定语从句.