He was naked to the waist. 他光着上身。
The girls are wearing white blouses and bright-coloured skirts. 姑娘们穿着白上身,花裙子。
It's getting cold. We'd better start wearing our padded jackets. 天冷了,棉衣该上身了。
牛津高阶第八版
美国韦氏词典
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维基百科 (自由的百科全书)