打酱油 (dǎ jiàngyóu) to buy some sauce, to be a bystander
Usage：
“打酱油”原指孩子大了可以帮家长做一些家务事。网络语境中，表示某人对话题漠不关心，或者在一项活动中没有起到任何作用。
“打酱油” originally referred to how kids, when they grow up, can help their parents with housework. When used on the internet, it means that someone is indifferent to a topic or can change nothing during an event.
Sentences：
1、Děng nǐ jiéhūn de shíhòu, wǒ érzi dōunéng dǎ jiàngyóu le.
等你结婚的时候，我儿子都能打酱油了。
等你结婚的时候，我儿子都能打酱油了。
When you get married, my son can help with chores.
2、Màidì zài Mǎcìduì yīzhí bànyǎn zhe dǎ jiàngyóu de juésè, dànshì tā duìcǐ bìng bú zàiyì.
麦蒂在马刺队一直扮演着打酱油的角色，但是他对此并不在意。
麦蒂在马刺队一直扮演着打酱油的角色，但是他对此并不在意。
McGrady played the role of bystander on the Spurs, but he doesn’t care.
