6 sentences

1. 敌我双方在边界爆发了冲突。

   dí wǒ shuāng​fāng zài biān​jiè bào​fā le chōng​tū.

   Conflicts broke out between the two sides at the border.

   Source: Dong Chinese Dictionary

2. 我们必须假设他们有人盯着边界。

   wǒ​men bì​xū jiǎ​shè tā​men yǒu rén dīng zhe biān​jiè.

   We have to assume they have eyes on the borders.

   Source: OpenSubtitles

3. 这条河流是两国之间的自然边界。

   zhè tiáo hé​liú shì liǎng guó zhī​jiān de zì​rán biān​jiè.

   This river is the natural boundary between the two countries.

   Source: Dong Chinese Dictionary

4. 军队在边界保持着严密的防守态势。

   jūn​duì zài biān​jiè bǎo​chí zhe yán​mì de fáng​shǒu tài​shì.

   The army maintains a tight defensive posture on the border.

   Source: Dong Chinese Dictionary

5. 两国签署了关于边界问题的协议书。

   liǎng guó qiān​shǔ le guān​yú biān​jiè wèn​tí de xié​yì​shū.

   The two countries signed an agreement regarding boundary issues.

   Source: Dong Chinese Dictionary

6. 那场战争结束后，双方在边界处交换了虏。

   nà cháng zhàn​zhēng jié​shù hòu, shuāng​fāng zài biān​jiè chù jiāo​huàn le lǔ.

   After the war ended, the two sides exchanged prisoners at the border.

   Source: Dong Chinese Dictionary