第23题: [单项选择]小红把平时节省下来的全部五分硬币先围成一个三角形,正好用完,后来又改围城一个正方形,也正好用完。如果正方形的每条边比三角形的每条边少用5枚硬币,则小红所有五分硬币的总价值是() A. 1元 B. 2元 C. 3元 D. 4元 参考答案:C 答案解析:正确答案是C考点和差倍比问题解析设围成三角形每条边上有x个硬币,每个顶点重复1次,则围成三角形硬币总数为3(x-1)个,同理围成正方形硬币总数为4(x-5-1),3(x-1)=4(x-5-1),解得x
A. A TV weather program on seasonal changes. B. An informal discussion between friends. C. An academic presentation at school. D. An advertisement for a city tour. 参考答案:C 答案解析:[听力原文] 14-16 Hello everyone. Today, I'd like to talk about the changing seasons in my city w