Across the busy plaza, vendors sell hot dogs and croissant sandwiches.在热闹广场的另一边，摊贩叫卖着热狗和羊角三明治。Vendors displayed their wares in baskets or on the ground.小贩们把他们的商品摆放在篮子里或地上。Vendors were doing a brisk trade in souvenirs.商贩们...
A digraph D is unilateral.有向图D是单连的.We shall abbreviate'directed graph'to digraph.我们将把“有方向的图”简称为方向图.There fore we study the kings of locally semicomplete digraph by its characterization.文章通过研究局部半完全有向图的结构定理,分类讨论了...