cheat by selling inferior
Jade and jade is an idiom, interpretation: show people is jade, sell people is stone, meaning the same as "hang sheep's head, sell dog meat.".
It means "hanging sheep's head and selling dog meat".
cheat by selling inferior
one 's hair is grayishly white at the temples - liǎng bìn rú shuāng
like a crane 's bone and a fowl 's skin - hè gǔ jī fū
make one last stand before the city wall - bèi chéng jiè yī