The boys,________had played the whole day long, were tired. A.all of what B.all of which C.all of them D.all of whom 答案:D了解物质的用途可以帮助我们更好地生活.请按下列要求选择合适的物质,用其编号填空.①氧气 ②稀硫酸 ③氯化钠 ④碳酸氢铵 ⑤干冰 ⑥生石灰(1)能支持燃烧的是______;(2)用来腌制食品的是______;(3)用来除铁锈的是______;(4)在农业上做氮肥的是______;(5)可用于人工降雨的是______;(6)常用作食品干燥剂的是______.