In “Detective on the Trail,” Bob Sugg knew that the man in polic

In “Detective on the Trail,” Bob Sugg knew that the man in police uniform was the criminal because the real policemen were dressed in _______.
【正确答案】：plain clothes
【题目解析】：原句的意思是“在《Detective on the Trail》这篇课文中，Bob Sugg知道穿着警服的这个男人就是罪犯，因为真正的警察是穿便服的”。