如何区分south,southern,southwest

如何区分south,southern,southwest south,the south,southern...如何运用（英语高手进） south,southern的区别 South China还是Southern China south 和southern 的区别 south和southern的区别 South Africa和Southern Africa区别? in south China /in southern China 区别 south和southern的用法与区别 south southern southest的区别与用法 south和southern之间的区别是什么? 英语方位词造句用northwest southwest southeast northeast south north