3 sentences

1. 他是一名边防战士。

   tā shì yī míng biān​fáng zhàn​shì.

   He is a border guard.

   Source: Dong Chinese Dictionary

2. 由于局势紧张，边防部队加强了戒备。

   yóu​yú jú​shì jǐn​zhāng, biān​fáng bù​duì jiā​qiáng le jiè​bèi.

   Due to the tense situation, border troops have increased their vigilance.

   Source: Dong Chinese Dictionary

3. 边防战士们冒着严寒，小心地跨过了那条国境线。

   biān​fáng zhàn​shì men mào zhe yán​hán, xiǎo​xīn de kuà​guò le nà tiáo guó​jìng​xiàn.

   The border guards braved the severe cold and carefully crossed the border line.

   Source: Dong Chinese Dictionary