题目

下列过程属于大气固氮的是（） A . 分离液态空气制氮气 B . 合成氨 C . 闪电时N2转化为NO D . 豆科作物根瘤菌将N2转化为NH3 答案：CWhat _______ he usually have _______ breakfast? A. do; for B. do; at C. does; for D. does; with