2 sentences for 脸色 (liǎn​sè — look)

1. 他的脸色忽地变了。

   tā de liǎn​sè hū​de biàn le.

   His expression suddenly changed.

   Source: Dong Chinese Dictionary

2. 看到老师严厉的脸色，学生们立刻安静了下来。

   kàn​dào lǎo​shī yán​lì de liǎn​sè, xué​sheng men lì​kè ān​jìng le xià​lai.

   Seeing the teacher's stern expression, the students immediately quieted down.

   Source: Dong Chinese Dictionary