第12题: [单项选择]I'm afraid this painting is not by Picasso. It's only a copy and so it's ______. A. priceless B. invaluable C. unworthy D. worthless 参考答案:D 答案解析:worthless意为“无价值的,无用的”;priceless意为“无价的,贵重的,无法估价的”,a priceless treasure意为“无价之宝”;invaluable意为“无法估价的,非常宝