阅读材料：Toward the end of his life, the Chevalier de Seingalt (1725-1798) wrote a long memoir recounting his life and adventures. The Chevalier was a somewhat controversial figure, but since he...
听力材料：The reading is correct in pointing out the problems associated with oil-powered cars. Yes, oil is a finite resource, and yes, burning oil harms the environment. However, the reading is ...
阅读材料：Car manufacturers and governments have been eagerly seeking a replacement for the automobile’s main source of power, the internal-combustion engine. By far, the most promising alt...
听力材料Well, ongoing investigations have revealed that predation is the most likely cause of sea otter decline after all.目前的研究表明天敌捕食是最可能导致海獭数量减少的...
阅读材料：The sea otter is a small mammal that lives in waters along the western coast of North America from California to Alaska. When some sea otter populations off the Alaskan coast started ra...
听力材料The evidence linking this portrait to Jane Austen is not at all convincing. Sure, the painting has long been somewhat loosely connected to Austen’s extended family and their descende...
阅读材料Jane Austen (1775-1817) is one of the most famous of all English novelists, and today her novels are more popular than ever, with several recently adapted as Hollywood movies. But we do no...
听力材料：Of course, there are some negative consequences of selling fossils in the commercial market, but they have been greatly exaggerated. The benefits of commercial fossil trade greatly outw...
阅读材料： Private collectors have been selling and buying fossils, the petrified remains of ancient organisms, ever since the eighteen century. In recent years, however, the sale of fossils, par...
听力材料：Salvage logging may appear to be an effective way of helping forests recover after a destructive fire or storm, but it can actually result in serious loner-term environmental damage. It...