lǎo / shī / xiān / shì / fàn / chǐ / yín / yīn / de / fā / yīn / wèi / zhì / zài / ràng / xué / shēng / liàn / xí

老师先示范齿龈音的发音位置，再让学生练习。

The teacher first demonstrated the articulation of alveolar sounds and then had the students practice.