U. S. alliances,treaties,and agreements serve not only to define clear lines against aggression,hut,by combining the resources of many nations,collective security agreements,also help all to share the common burden.

• 美国与其他国家建立同盟关系，签署条约和协议，不仅可以划定明确的反侵略阵线，而且通过联合使用许多国家的资源，制定集体安全协定，并帮助大家分担共同的义务。