3 sentences

1. 敌军在边境线上布雷。

   dí​jūn zài biān​jìng​xiàn shàng bù​léi.

   The enemy forces are laying mines along the border.

   Source: Dong Chinese Dictionary

2. 我方的侦察机在边境线上空执行日常监视任务。

   wǒ​fāng de zhēn​chá jī zài biān​jìng​xiàn shàng​kōng zhí​xíng rì​cháng jiān​shì rèn​wu.

   Our reconnaissance plane is conducting routine surveillance missions over the border line.

   Source: Dong Chinese Dictionary

3. 我军在边境线上的行动成功牵制了敌方的主力。

   wǒ jūn zài biān​jìng​xiàn shàng de xíng​dòng chéng​gōng qiān​zhì le dí​fāng de zhǔ​lì.

   Our army's actions on the border successfully pinned down the enemy's main forces.

   Source: Dong Chinese Dictionary