题目

某化合物由碳、氢、氧三种元素组成，红外光谱图显示有三种共价键的振动吸收，核磁共振氢谱图显示有三个峰，峰面积比为6：1：1，则该有机物的结构简式是（    ）     A．C2H5OCH3                     B．CH3CH（OH）CH3     C．CH3CH2CH2OH                      D．CH3CH2CHO 答案：B_______ our teacher is very busy, _______ he often help us with our lessons. A.Though; or B.Though; but C./ ;but D./ ;though