For example, children can learn how to show good manners and get along with others. These are important skills in adult life.

例如，孩子们可以学习如何表现出良好的举止以及如何与他人相处。这些都是成年生活中的重要技能。 

 If we don't have rules to stop using bad language or bullying others, they will not know how to deal with social relationships in adulthood.这句话的意思是：如果我们没有（制定）规则来制止使用脏话或欺负他人（这类行为），那么他们在成年后将不知道如何处理社会关系。