His muscles were long and smooth, like those of a panther.
他的肌肉长且平滑,像豹子的一样。
2
A key discovery was that if the inside of the mask is smooth - even if the outside is bumpy with pores, a nose and other features - it will stretch over most faces and move with facial muscles.
As you strengthen them, you start to see things like the muscles of your cheeks being lifted, your nose lifting up, your eyes becoming wider, your mouth corners turning up, fine lines become smooth.