He sat down in the armchair and turned on the radio.

他在扶手椅上坐下来，打开了收音机。

《柯林斯英汉双解大词典》

She sat in the armchair.

她坐在那张扶手椅子里。

youdao

He found a cat sleeping in the armchair.

他发现一只猫在扶手椅上睡觉。

youdao

The Frenchman sat on the couch, but then he wanted to sit awhile in the armchair.

NEWYORKER: So It Is in Life

Then the Frenchman decided to lie down on the couch and rest, but before he made it to the couch he veered off to the side and sat down in the armchair.

NEWYORKER: So It Is in Life

When her parents visited her in Brooklyn, after Akash was born, her father claimed an armchair in the living room, quietly combing through the Times, occasionally tucking a finger under the baby's chin but behaving as if he were waiting for the time to pass.

NPR: Excerpt: 'Unaccustomed Earth'