题目

如图,梯形ABCD是等腰梯形,AD∥BC,求证:A、B、C、D共圆.图2-2-5 答案：证明:∵梯形ABCD是等腰梯形,∴∠A=∠D.又∵AD∥BC,∴∠C+∠D=180°.∴∠A+∠C=180°.∴A、B、C、D共圆.—Look! There ________ so many cars in our city.—Yes, and I think there ________ more cars in the future.A. are; areB. are; will beC. will be; areD. will be; will be