某温度下，在2L密闭容器中投入一定量的A，B发生反应：3A（g）+bB （g）⇌cC（g）△H=﹣Q kJ•mol^﹣1（Q＞0）．12s 时达到平衡，生成C的物质的量为0.8mol，反应过程如图所示．下列说法正确的是（   ）

阅读材料回答下列各题
材料一：“杀死或伤害奴隶，不算犯罪，只须向主人赔偿损失；拐带、帮助奴隶逃跑或窝藏奴隶者，都要处以死刑。……”
材料二：“通过抽签，所有公民都可以担任各级官职；公民大会决定国家一切大事，任何公职人员不能专权，担任公职和参加城邦活动的……公民广泛参政。”
请回答：
（1）上述材料反映的奴隶制分别是什么地区的？
（2）材料一内容的出自于哪部法典？它的发现有何重要的历史意义？
（3）材料二中的“国家”指的是哪一城邦国家？这个“国家”在谁当政时期成为地中海的霸主？

北半球一天中陆地气温的最高值出现在____ ，最低值出现在____ 

根据短文内容，选择正确答案
B
    We can not live a modern life without travelling. The fastest way of travelling is by air. With a plane one can travel in one day to places which it takes a month or more to get to a hundred years ago. 
    Travelling by train is slower than by plane, but one can see the country while-he is travelling through. Modern trains have comfortable seats and dining-cars. They make even the longest journey enjoyable.
    Some people prefer to travel by sea when possible. There are large luxury liners(客轮) or river boats. They are not as fast as trains or planes, but travelling by sea is a very pleasant way to spend a holiday.
    Many people like to travel by car. They can make their own timetable. They can travel hundreds of miles a day, just as their wish. They can stop wherever they want to see something interesting or to enjoy a good meal at a good restaurant, or to spend the night at a hotel. That is why people choose travelling by car for pleasant trips, while they usually take trains or planes for business.

$\frac{15}{16}÷\frac{3}{8}=$ （   ）