Bring me a chair to sit on.的on是表示什么?

Bring me a chair to sit on.的on是表示什么? 是sit in a chair还是sit on a chair? I found a chair to sit on i haven't got a chair( ) a:to sit b:to sit on c:for me to si sit in a chair sit on区别 sit on chair的意思! sit on chair的意思 sit in a chair还是sit on a chair? 是sit on the chair还是sit in the chair there is no chair for me to （sit） 还是 （sit on） sit on the chair Please give me a chair____. A.to sit on B.to sit C.sit on 这道