上句见：Day374
The Story of Philosophy《哲学的故事》第1章Plato第7节VI. The Psychological Solution第8段第2句：

With minds so freely growing, and bodies made strong by sport and outdoor life of every kind, our ideal state would have a firm psychological and physiological base broad enough for every possibility and every development. But a moral basis must be provided as well; the members of the community must make a unity; they must learn that they are members of one another; that they owe to one another certain amenities and obligations. Now since men are by nature acquisitive, jealous, combative, and erotic, how shall we persuade them to behave themselves? By the policeman's omnipresent club? It is a brutal method, costly and irritating. There is a better way, and that is by lending to the moral requirements of the community the sanction of supernatural authority. We must have religion.
浙江大学译本：然而，道德的地基也必须打好；社会成员必须团结一致，他们必须认识到互相之间的成员关系，彼此承担一定的责任和义务。

解析

1、But a moral basis must be provided as well;
我们仍需构建道德基石；
2、the members of the community must make a unity;
社会成员必须形成共同体意识；
make a unity：强调社会凝聚力，比“unite”更正式，适用于分析社区、国家的团结问题（如移民融入、文化多样性）。
3、they must learn that they are members of one another;
他们必须意识到他们是彼此相互依存；
4、that they owe to one another certain amenities and obligations.
他们彼此负有一定的礼仪规范和义务。
amenity: something makes life easy or more pleasant 生活福利设施；便利设施
Amenities: used for things that make life more pleasant or comfortable.（复数形式）统指一切使人生愉快的有形和无形的大小事物，如公园、好的学校和礼貌等都是。
By this time all the amenities and gentlenesses of the Southland had fallen away from the three people. 此时，这三个人已然丧失了南方地区所有的舒适惬意和温和优雅。《野性的呼唤》

这里讲述了构建理想国的条件之三——道德基石。这是除前面身心基础之外的另一个重要的基石。

我们仍需构建道德基石；社会成员必须形成共同体意识；认识到彼此相互依存且负有一定的礼仪规范和义务。