2 sentences for 固 (gù — solid)

1. 这种胶水粘得不固，东西很容易掉。

   zhè zhǒng jiāo​shuǐ zhān de bù gù, dōng​xi hěn róng​yì diào.

   This glue doesn't hold firmly; things fall off easily.

   Source: Dong Chinese Dictionary

2. 这个化学反应涉及到气、液、固三相的转化。

   zhè​gè huà​xué fǎn​yìng shè​jí dào qì, yè, gù sān xiàng de zhuǎn​huà.

   This chemical reaction involves the transformation of gas, liquid, and solid phases.

   Source: Dong Chinese Dictionary