2 sentences for 行当 (háng​dang — profession)

1. 他从小就跟着父亲学习木匠这个行当。

   tā cóng xiǎo jiù gēn​zhe fù​qīn xué​xí mù​jiàng zhè​ge háng​dang.

   He has been learning the trade of carpentry from his father since he was a child.

   Source: Dong Chinese Dictionary

2. 在某些地下场所，有人专门从事做鸭的行当。

   zài mǒu​xiē dì​xià chǎng​suǒ, yǒu rén zhuān​mén cóng​shì zuò​yā de háng​dang.

   In some underground establishments, some men work as male prostitutes.

   Source: Dong Chinese Dictionary