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    Deep in the forest in the northern part of the Republic of Congo, scientists have made a surprising discovery．Researchers discovered more than 125,000 critically endangered western lowland gorillas．

    In the 1980’s,scientists estimated that the total population of western lowland gorillas in Central Africa was fewer than 100,000．Since then, however, the scientists believed this number had been reduced by at least half．They thought the animals were being killed off by hunters and diseasses, especially the deadly Ebola virus．

    The new population count was the result of intensive work by the Wildlife Conservation Society and scientists of the Republic of Congo．They searched rainforests, looking for gorilla nests．Gorillas build beds, or nests, for sleeping each night．The researchers use the number of nests they find to help estimate the local gorilla population．They found some forests had population densities that were among the highest ever recorded．The researchers studied an area of 47,000 square kilometers．

    The scientists say the higher number of gorilla is the result of efforts by the Republic of Congo to take care of its protected areas．The gorillas have also done well because they live in areas far away from people．And they have plenty  to eat．Wildlife Conservation Society president Steven Sanderson said the success of the gorillas is the proof that humans can help protect animal species in danger of disappearing．

    Western lowland gorillas are one of four recognized gorilla subspecies(亚种)。 Other subspecies include mountain gorillas,eastern lowlang gorillas, and Cross River gorillas．The International Union for Conservation of Nature considers all of the subspecies to be critically endangered, except for the eastern lowland gorillas．That subspecies is considered endangered．

1.How do the researchers decide the local gorilla population? (No more than eight words)

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2.What’s the researchers’attitude towards the present western lowland gorilla population? (No more than seven words)

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3.What is the main idea of the fourth paragraph?(No more than eight words)

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