1. During World War II, some countries entered into cobelligerency with each other to fight against a common enemy.
在第二次世界大战期间，一些国家相互之间进行了共同作战，以打击共同的敌人。

2. Cobelligerency often involves military cooperation and strategic coordination between two or more parties.
共同作战通常涉及到两个或多个方面之间的军事合作和战略协调。