硬化（的）；稠厚（的）的英文

• stiff

• 硬化:    harden; stiffen; stiffening; ...
• 的:    4次方是 The fourth power of 2 i ...
• 稠厚:    stiff
• …的:    -al
• 的:    4次方是 The fourth power of 2 is direction