题目

I don't know the reason ______ you were absent from the meeting, but I'm sure someone will tell me the reason ________ you haven't told me. A . why; that B . that; why C . Because; which D . of which; that 答案：A狮子和老虎是不同的物种，但是自70年代以来，先后有若干家动物园培育出了可育的杂种“狮虎”或“虎狮”。由此看来，进化历史上的隔离可能主要是A.地理隔离B.求偶方式不同C.繁殖期不同D.遗传组成的差异