sit down 坐下，对应的词是 stand up起立

sit down释义：坐下来；坐下；就座；使坐下；使就座

例句：Stop fooling around and sit down!

别干傻事了，坐下来！

'Sit down', she said.

“坐下。”她说。

stand up释义：站；立；站立；起立；站起来；

例句：There were no seats left so I had to stand up.

没有座位了，所以我只好站着。

Be careful not to bump your head on the beam when you stand up.

当心站起来时头别撞了横梁。