他选择了一件灰色毛衣背心搭配条纹衬衫，看起来既正式又时尚。

He chose a gray ___sweater-vest with a striped shirt, looking both formal and stylish.

他喜欢在衬衫外面穿一件针织背心，既保暖又时尚。

He likes to wear a ___sweater-vest over his shirt, which keeps him warm and stylish.