他一边工作一边唱歌 She sang ___ the worked
问题描述：
他一边工作一边唱歌 She sang ___ the worked
答
when.不能填while,因为while后面是she was working.
他一边工作一边唱歌 She sang ___ the worked
when.不能填while,因为while后面是she was working.