4 sentences for 十五 (shí​wǔ — fifteenth)

1. 农历七月十五是中元节。

   nóng​lì Qī​yuè shí​wǔ shì Zhōng​yuán​jié.

   The fifteenth day of the seventh lunar month is the Ghost Festival.

   Source: Dong Chinese Dictionary

2. 正月十五是元宵节。

   Zhēng​yuè shí​wǔ shì Yuán​xiāo​jié.

   The fifteenth day of the first lunar month is the Lantern Festival.

   Source: Dong Chinese Dictionary

3. 中秋节是在农历八月十五。

   Zhōng​qiū​jié shì zài nóng​lì Bā​yuè shí​wǔ.

   The Mid-Autumn Festival is on the 15th day of the eighth lunar month.

   Source: Dong Chinese Dictionary

4. 正月十五是中国的元宵节。

   Zhēng​yuè shí​wǔ shì Zhōng​guó de Yuán​xiāo​jié.

   The fifteenth day of the first lunar month is China's Lantern Festival.

   Source: Dong Chinese Dictionary