3 sentences for 入 (rù — entering tone)

1. 四声包括平、上、去、入。

   sì shēng bāo​kuò píng, shǎng, qù, rù.

   The four tones include level, rising, departing, and entering.

   Source: Dong Chinese Dictionary

2. 入是古代汉语的四个声调之一。

   rù shì gǔ​dài Hàn​yǔ de sì gè shēng​diào zhī yī.

   The 'entering tone' is one of the four tones of ancient Chinese.

   Source: Dong Chinese Dictionary

3. 在学习中国古代音韵学时，需要区分平、上、去、入。

   zài xué​xí Zhōng​guó gǔ​dài yīn​yùn​xué shí, xū​yào qū​fēn píng, shǎng, qù, rù.

   When studying ancient Chinese phonology, it is necessary to distinguish between the level, rising, departing, and entering tones.

   Source: Dong Chinese Dictionary