设 G 是一个连通图,不含奇点,则从 G 中去掉任一条边后,得到的图必定为 。
Goods are carried by several of transport--on road or rail, by sea or air.
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
免费的网站请分享给朋友吧