阅读下面的文字，完成文后各题。

       汀州至宋代已成为客家人聚居的最大城市，其繁华的程度是：“十万人家溪两岸，绿杨深锁济川桥□□随着推移的历史，客家人又沿着汀江流域不断向外迁徙，到达广东，甚至漂洋过海。无论走多远，身在何方，客家人的印记总是伴随着子孙后代。千年汀江水bǔ育了勤劳的客家人，坚固的城墙却________（A．坚持  B．坚守）了一种独特的客家文化。客家首府繁华得有点朴实，也许由迁徙的性格构建而成的城市注定了没有帝都省城的大气。这座繁华一时的客家首府在崇山峻岭的包围中，像是做了一个________（A．穿越  B．逾越）时空的深沉的梦，一梦醒来，汀水依旧。

函数f（x）=lg$\frac{1-x}{x-4}$的定义域为（　　）

China is very famous(著名的) for its food in the world. There are many kinds of food in China. They're Cantonese(广东的) food, Sichuan food, Shanghai food, Hunan food and so on. And I like Sichuan food best.
Now, Sichuan food is very popular. There are many Sichuan food restaurants all over the country. Sichuan food is very hot(辣的), but people love it. In some famous Sichuan food restaurants, you can see many people waiting there. Now in Beijing, there are more and more Sichuan food restaurants.

某三棱锥的三视图如图所示，该三棱锥的体积是（　　）