2 sentences for 老掉牙 (lǎo​diào​yá)

1. 那台老掉牙的录音机快转不动了。

   nà tái lǎo​diào​yá de lù​yīn​jī kuài zhuàn bù dòng le.

   That ancient tape recorder is barely working anymore.

   Source: Dong Chinese Dictionary

2. 这种老掉牙的理论早已被现代科学推翻了。

   zhè zhǒng lǎo​diào​yá de lǐ​lùn zǎo​yǐ bèi xiàn​dài kē​xué tuī​fān le.

   This obsolete theory has long been overturned by modern science.

   Source: Dong Chinese Dictionary