tell from的使用方法

You could tell from their faces and their eyes that they found the joke funny, but not one of them was going to laugh, and give him the chance to win the competition.

tell是分辨的意思，that从句做tell的宾语，from做状语吗？

网友的理解完全正确。from their faces 表示“从他们脸色上；依据他们的脸色”。在这里作“方法状语”，修饰tell。