中文摘要：

利用图论术语,对有限全变换半群Tn的D-类的极大子半群进行了直观的刻划。设IE（Dr）,若G（I）为极大rectangle-完全子图,则T=∪e∈IHe是Dr的极大子半群。反之,Dr的任意极大子半群必有上述结构。

英文摘要：

Using the concepts of graph theory,this paper characterized the maximal subsemigroups of Dclasses directly.Let IE（Dr）.if（G）I was the maximal rectangle-complete subgraph,then T=∪e∈IHe must be the maximal subsemigroup of Dr.Conversely,every maximal subsemigroup of Dr must be of the type.