JH_002
综合写作
听力音频：
Yellow-legged mountain frogs live in the Sierra Nevada mountains in California in the western United States. They live around sunny streams and lakes at high altitudes. Over the last 40 to 50 years, populations of the yellow-legged mountain frog have been declining, and it is now considered an endangered species. Researchers have suggested several theories about what may have caused the population decline.
Nonnative Trout
Some researchers have suggested that the problem is the introduction of trout (a species of fish) into water sources in the Sierra Nevada mountains. The trout were introduced to encourage recreational fishing, but they may be causing the frog decline. Trout are predatory fish that can feed on tadpoles (young frogs). Since trout are not native to the region, yellow- legged mountain frog tadpoles have not developed any defensive behaviors that would protect them from the trout.
Pesticides
Others believe that chemical pesticides sprayed onto farm fields could be poisoning frog habitats and harming frog populations. To the west of the Sierra Nevada mountains lies California’s Central Valley, a region with some of the most intensive agriculture in the United States. Pesticide use in the Central Valley is heavy, and it is possible that some amount of the pesticide contaminates the freshwater habitats of the yellow-legged frog.
Fungal Disease
In recent years, a fungal disease called chytridiomycosis has been reducing or even wiping out frog populations in many areas around the world. Chytridiomycosis typically attacks the skin; a frog’s skin is essential to many of its vital functions, including breathing and water intake. The fungus that causes chytridiomycosis has been found in the Sierra Nevada mountains, and it is quite possible that it is to blame for the decline of the yellow-legged mountain frog populations there.
Question:Summarize the points made in the lecture, being sure to explain how they respond to the specific concerns expressed in the reading passage.
学术写作：
Doctor Gupta
We are looking this week at different ways businesses market their products and services especially nontraditional methods. One thing that marketers pay close attention to is online reviews of their products. A business might include customer reviews on their website or carefully monitor the reviews on third-party sites. I would like you to discuss your own experiences with online reviews. Do you find them useful when deciding whether or not to buy a product or service? Why or why not?
Claire
I think online reviews are a great source of information because they are written by ordinary customers who are like me. For instance, when I read a restaurant review by a professional food critic, I’m not interested in some of the details that are included, like how the food is prepared. I’m more interested in aspects like the quality of the food and the service, which regular customers usually comment on.
Andrew
To me, online reviews have some real problems. First, people are more likely to post reviews after a bad experience than after a good one. As a result, what you read is often weighted toward the negative. Also, you have no way of knowing whether reviewers know what they are talking about or even if they actually bought and used the product they are reviewing.
