综合写作：
The American burying beetle was once a common insect in the United States, with populations found in most states a hundred years ago. Since that time, the population of the American burying beetle has been steadily declining; right now, populations remain in only a handful of states. There are several theories about why the species has almost been wiped out.
One theory is that the species is declining because of pesticides that are used by farmers. Farmers use pesticides to protect crops from insects that, unlike the American burying beetle, are harmful to their crops. Even thoughto protect crops from insects that, unlike the American burying beetle, are harmful to their crops. Even though burying beetles are not the targets of these agricultural pesticides, the pesticides leak into the ground and may be poisoning the beetles living there.
A second theory suggests that development of more and more land in the United States by humans over the past century has destroyed the habitats that support the American burying beetle populations. The American burying beetles bury their food in the ground in order to feed their young. They need a habitat where the soil is soft enough for them to dig and burrow, and where the appropriate food sources are plentiful. However, human development has broken up the continuous habitats suitable for the beetle into smaller, fragmented areas. Habitat fragmentation could well be the cause of the American burying beetle’s decline.
Third, some researchers believe that competition with other animals is the main problem for the beetles. Over the past hundred years, populations of small scavenger mammals have increased in the United States. Some of the small scavenger mammals have the same food sources that the burying beetles do; the burying beetle may be dying out because it is losing an increasingly intense competition for food.
学术写作：
教授：所有的科学发现是否都应该分享？
Kelly：不是。
Andrew：是。
Doctor Achebe: This week’s course material will focus on scientific discoveries. While scientific researchers usually prefer to share what they learn with other scientists, many businesses and governments keep certain scientific discoveries secret. Some people believe that all scientific findings should be shared freely among scientists all around the world and that governments and businesses should not keep any discoveries secret. What do you believe and why?
Kelly: I don’t think all discoveries should be shared. Businesses, for example, often spend a lot of money on scientific research in order to make a discovery that can lead to profit. Even if that discovery benefits everyone, the business has a right to keep the discovery secret so that it can develop a profitable product from the research.
Andrew: Sharing knowledge is crucially important to most scientists. Scientists usually publish the details of their discoveries in scientific journals, which means that everyone can see what the scientists have accomplished. Being recognized as the person who made a discovery is the biggest reward for any scientist. When scientists keep their discoveries secret, they lose that recognition. That is very unsatisfying.
