按照我国土地管理的政策规定，经营性必须采用招标、拍卖和挂牌的方式公开出让。对于这几种出让方式，在进行底价评估时应采用（）价值标准。

A．出让合同

B．成本

C．完全产权

D．公开市场

—I just wonder       that made Mark Twain so famous a writer.

—Of course his early experiences.

A．it was what

B．what he did

C．how he did

D．what it was