The little boy has learned many Tang dynasty poems _____ though he is very young. A. by heart B. by mind C. by the way D. by book 答案:A下列说法中正确的是A.氯化钠的电子式是B.按照不同分类标准,KAl(SO4)2属于强电解质、硫酸盐、酸式盐C.标准状况下,2.24 L C2H6中含有0.6 NA对共用电子对D.Mg、F2、H2O2依次是只有还原性、只有氧化性、既有氧化性也有还原性