题目

As a result of destroying the forests, a large ____ of desert ___ covered the land. A . number; has B . quantity; has C . number; have D . quantity; have 答案：B下列各组中，两者之间不属于同位素及同素异形体的是（ ）A．1H和2HB．白磷和红磷C．K和CaD．金刚石和石墨