3 sentences

1. 两人靠着共同的兴趣维系着这段长久的友谊。

   liǎng rén kào zhe gòng​tóng de xìng​qù wéi​xì zhe zhè duàn cháng​jiǔ de yǒu​yì.

   The two of them maintain their long friendship through shared interests.

   Source: Dong Chinese Dictionary

2. 健康的性爱被认为是维系夫妻关系的重要因素之一。

   jiàn​kāng de xìng'ài bèi rèn​wéi shì wéi​xì fū​qī guān​xi de zhòng​yào yīn​sù zhī yī.

   Healthy sex is considered one of the important factors in maintaining a relationship between a couple.

   Source: Dong Chinese Dictionary

3. 共同的文化传统将这个庞大的群体维系在一起。

   gòng​tóng de wén​huà​chuán​tǒng jiāng zhè gè páng​dà de qún​tǐ wéi​xì zài​yī​qǐ.

   Common cultural traditions hold this massive group together.

   Source: Dong Chinese Dictionary