九(1)班同学在一次探究性学习中形成了以下结论：它充分体现了资本原始积累的血腥性；它客观上促进了新大陆的开发；它把灾难带给了非洲这片古老的大陆，部族之间战争被挑起，上亿人口被掠夺。据此可知，他们探究的问题是（      ）

    During holidays，Kitty usually goes to see the exhibits in many museums，such as the history museum，the art museum，the museum of science and technology and the museum of natural history．There are thousands of wonderful things in museum.There are paintings，sculptures(雕塑)，costumes(服饰)，swords(剑)，ancient animal bones and plants，stuffed animals(动物标本)and many others．It is always a good review of history to visit those museums．It is also a great way to learn more things by myself．

①市场在铁路票价的定价中将发挥其基础性作用，宏观调控从此退出

②我国社会主义市场经济是同社会主义基本制度结合在一起的

③今后铁路票价的定价仍需法律、道德来规范和引导

④市场中“看不见的手”将引导铁路经营者制定票价