When I was back home last night, my father _______ a newspaper in the living room. A. was reading B. is reading C. read D. reads 答案:A
有机物甲、乙、丙、丁都是由C、H、O三种元素组成且也都只含有一种官能团.实验证明,丁氧化可得丙,乙氧化可以得到丙或丁,甲水解得乙和丙.假如用M表示物质的摩尔质量,则下列各式中正确的是( ) A. M(丙)>M(丁)>M(乙) B. M(丙)>M(乙)>M(丁) C. M(甲)=M(乙)+M(丙) D. 2M(丁)=M(乙)+M(丙)