在拉丁美洲，推翻美国扶植的傀儡政权，建立革命政府，并走上社会主义道路的国家是（　　）​

我国唐朝的张志和在《玄贞子》中记载了著名的“人工虹”实验，“背日喷乎水，成虹霓之状”.该现象产生的原因是（  ）

将直线y=2x-4绕着其与x轴的交点逆时针旋转$\frac{\pi }{4}$得到直线m，则m与圆x²+y²=4截得弦长为（    ）

某初级中学共有学生2000名，各年级男、女生人数如下表：

已知在全校学生中随机抽取1名，抽到初二年级女生的概率是0.19．

（1）求x的值；

（2）现用分层抽样的方法在全校抽取48名学生，问应在初三年级抽取多少名？

    Welcome to our club l Our club is a good place to have fun for students. We have ten sports teachers and five art teachers. Here you can learn to play tennis and you can learn to draw（画画）.And we have many great activities. October is a busy month. On October 5th,we have a trip in the morning. And on October 20th,we have two games, a tennis game and a baseball game. Your parents can come to the club to watch the games. On December 18t",we have a music festival. It's very interesting. And on December 23nd,we have an English party.

    In the club, we have a food store. You can have lunch or dinner here. Come and have a good time here !