2 sentences

1. 他们两国结成了紧密的同盟。

   tā​men liǎng guó jié​chéng le jǐn​mì de tóng​méng.

   The two countries formed a close alliance.

   Source: Dong Chinese Dictionary

2. 这两个国家建立了长期的同盟关系。

   zhè liǎng gè guó​jiā jiàn​lì le cháng​qī de tóng​méng guān​xi.

   These two countries have established a long-term alliance.

   Source: Dong Chinese Dictionary