题目

读—读，连—连。① Spring isA. hot and the days are long.② Summer isB. green with flowers and songs.③ Autumn is C. white and the year is gone.④ Winter isD. golden and farmers are busy. 答案：【1】B【2】A【3】D【4】C16．写出符合题意的物质的化学式：可以改良酸性土壤的物质为Ca（OH）2；可以用作复合肥的盐为KNO3；空气的主要成分之比，可用于食品保鲜的物质为N2．