题目

若方程ax2＋by2＝c(ab≠0，c＞0)表示焦点在x轴上的椭圆，则A.a＞b＞0                                         B.a＞0,b＞0C.b＞a＞0                                         D.＞ 答案：解析:将原方程整理成标准形式:＝1,则应满足＞＞0，又c＞0，∴b＞a＞0.答案:CIn April, the weather in some places in Shanxi was really changeable. People still remember they have __________four seasons in a week.A.organizedB.experiencedC.describedD.decided