单选题
The government issued a warning to local companies that all waste must be disposed of ______ or they will face heavy fines.
【正确答案】
D
【答案解析】[解析] 政府向当地企业发出警告：所有废弃物必须妥善处理，否则企业将被处以大量罚金。“all waste must be disposed of”语法结构完整，横线处应填入修饰“be disposed of”的副词，故D为正确答案。