17世纪40年代，伴随着明王朝的灭亡，清王朝建立起在全中国的统治。而同一时期的英国，也经历了一场不同含义的“革命”，这一“革命”最终结束了旧王朝的统治，建立了一个新的“王朝”。正是从这个时候开始，世界的天平开始失衡，东方的没落和西方的崛起都明显加快。从历史发展的趋势看，东西方“天平”失衡主要是指（    ）

某工厂生产一种仪器的元件，由于受生产能力和技术水平的限制，会产生一些次品，根据经验知道，其次品率P与日产量x(万件)之间大体满足关系： (其中c为小于6的正常数)．  (注：次品率＝次品数/生产量，如P＝0.1表示每生产10件产品，有1件为次品，其余为合格品)，已知每生产1万件合格的元件可以盈利2万元，但每生产出1万件次品将亏损1万元，故厂方希望定出合适的日产量．

正四棱锥的顶点都在同一球面上，若该棱锥的高为4，底面边长为2，则该球的体积为（   ）

阅读理解

C

    Hello! My name is Jack.I am from England.Now I am in China with my parents.I like China.I like Chinese food，too.I have breakfast at home.I eat an egg，some bread and porridge(粥) for breakfast.I don't like milk.I have no time to go home for lunch，so I have it at school.The lunch at school is very good.I often have noodles and dumplings.Noodles are my favourite food. Sometimes I have different foods for lunch.I eat rice，meat and vegetables.I always go home early in the afternoon.Then I do my homework.I have supper with my parents.Sometimes we go out to have dinner with our friends.We are happy in China.

—What __________ is our Chinese national flag (国旗)?   

—It's red.