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  • VOA标准英语2010年-Invasive Asian Carp Threaten Ecosystem

    Asian Carp now outnumber native fish in many areas of the United States and their expansion particularly threatens the fragile ecosystems of the Great Lakes. In an effort to control algae growth, catfish farmers in the southern United States introduc...

  • SSS 2008-09-18

    This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute. Breaking a mirror means seven years bad luck. So does spilling salt or meeting a black cat. Weve all heard such silly-sounding superstitions. Of course w...

  • SSS 2008-07-24

    This is Scientific American's 60-Second Science. Im Karen Hopkin. Itll just take a minute. When you think about an ecosystem, you usually think of the big animals that live there. The Serengetis ruled by lions. And estuaries are populated by fishes,...

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