第6题: [单项选择]Advertising media like direct mail, radio, television and newspapers ______ to increase the sales of industrial products. A. have been used B. will be used C. is being used D. has been used 参考答案:A 答案解析:根据句意,应用完成时的被动语态,media 是medium 的复数形式。同样单复数变化的词还有bacterium—bacteria(细菌),datum--data(数据)等。