题目

4世纪时，统一黄河流域的少数民族及其建立的政权是（ ） A . 匈奴、汉 B . 氐族、前秦 C . 鲜卑、燕 D . 羯族、前秦 答案：BThe factory which I visited yesterday was not the one              I once worked. A. where B. which C. what D. that