The Greek City-States: Sparta and Athens Of the hundreds of city-states that evolved during the Archaic Age, (800- 479 B.C.), Sparta and Athens stand out for their vividly contras...

The Search for the Origins of Writing     Who invented the first writing? Like many questions of its type in archaeology, this one is not easily answered. Some might arg...

The Origin of Flight in Birds 题目： Debate over avian origins was stimulated in 1861 when the 150-million-year-old fossil of a bird-like creature was unearthed. Called Archaeopt...

TF阅读真题第686篇Physiological Adaptations of Tuna

TF阅读真题第730篇The Human Appendix

    Economics begins with the assumption that human actions are rational-intended for maximum self-benefit. For example, people pay more for a larger box of the same cer...

TF阅读真题第701篇The Domestication of Dogs

TF阅读真题第818篇Easter Island statues

TF阅读真题第781篇Origins of the Deciduous Forests

The Origin of Mars's Moons     Mars has two tiny moons, Phobos and Deimos. The orbits of both these satellites are nearly circular and close to the planet: Phobos orbits...