5 sentences

1. 请在这张纸的反面签字。

   qǐng zài zhè zhāng zhǐ de fǎn​miàn qiān​zì.

   Please sign on the back of this sheet of paper.

   Source: Dong Chinese Dictionary

2. 我们要看清事物的正面和反面。

   wǒ​men yào kàn​qīng shì​wù de zhèng miàn hé fǎn​miàn.

   We need to see both the positive and negative sides of things.

   Source: Dong Chinese Dictionary

3. 我们必须看到事情的反面，不能只看表面。

   wǒ​men bì​xū kàn​dào shì​qing de fǎn​miàn, bù néng zhǐ kàn biǎo​miàn.

   We must see the other side of things, not just the surface.

   Source: Dong Chinese Dictionary

4. 他总是把旧作业本的反面也写满，生活非常节省。

   tā zǒng​shì bǎ jiù zuò​yè​běn de fǎn​miàn yě xiě​mǎn, shēng​huó fēi​cháng jié​shěng.

   He always fills the back of his old notebooks with writing; he leads a very frugal life.

   Source: Dong Chinese Dictionary

5. 他是一个反面教材，大家要引以为戒。

   tā shì yī gè fǎn​miàn jiào​cái, dà​jiā yào yǐn​yǐ​wéi​jiè.

   He is a negative example that everyone should learn from.

   Source: Dong Chinese Dictionary