题目

Tom, turn down the music. Why    you make such a big noise while your baby sister is sleeping?  A．must               B．would                     C．should             D．may 答案：A 解析: 略绿色植物的光合作用为地球生物提供了：①食物来源?? ②空气来源?? ③氧气来源?? ④能量来源A.①②③?? B.①②④?? C.②③④?? D.①③④