指雁为羹 zhǐ yàn wéi gēng 负薪之忧 fù xīn zhī yōu 言之谆谆，听之藐藐 yán zhī zhūn zhūn，tīng zhī miǎo miǎo 良工巧匠 liáng gōng qiǎo jiàng