The Collapse of Copán 题目：   The ancient Mayan kingdom of Copan, in what is now western Honduras, flourished for many years in the first millennium but declined sharpl...

题目：   Peruvian farmers have used guano (dried waste of seabirds) as a plant fertilizer since ancient times, but guano was not exported to Europe until 1840. Guano has mu...

TF阅读真题第824篇Asphalt

TF阅读真题第734篇The Sound Revolution in American Film

Martian Volcanoes       Earth is not the only planet to have volcanoes; in fact Mars-though all of its volcanoes have long been inactive-has the two largest ones i...

TF阅读真题第703篇Ice Age Triggers

TF阅读真题第819篇The Growth of Play in Children

TF阅读真题第783篇The European Agricultural Revolution in the Sixteenth Century

重复时间 2024-06-18 2024-09-28 2025-02-22 Equestrian Portraits in the Eighteenth and Nineteenth Centuries     It was common for European rulers from the eighteenth ...

  Sunspot Cycles   Dark regions on the Sun, called sunspots, were studied in 1610 by Galileo, who turned the newly invented telescope on objects in the sky. A lively deba...