While at work, sit upright, with a straight-back, in your chair.

工作时可以坐直，坐在椅子上要挺直腰杆。

youdao

Ten to fifteen minutes before going to bed find a quiet, uncluttered, and comfortable room and sit in a comfortable chair with a high back.

睡前十至十五分钟可以在安静舒适的房间里，坐在高背椅上躺一会儿，舒展一下筋骨。

youdao

He takes out his cigarettes and goes out to the back with a can of beer. ~ see him sit in the lawn chair and pick up the newspaper again.

我看见他坐到草坪上的躺椅里，又抄起了报纸。

youdao

Rather than sitting in a leather chair talking with someone reclined on a matching leather couch, I sit in the back of the classroom.

FORBES: Lemon Squares and the Acceptance Thereof