综合写作：
Chinook salmon, the largest salmon species in the Pacific Ocean, have largely disappeared along the coast of Alaska in the United States. Fishing restrictions have failed to solve the problem; in fact, the main cause of the decline is still unclear. Scientists have proposed several theories to explain the decreasing Chinook salmon numbers in Alaska.
Competition for Food
One possibility is that another salmon species—pink salmon—is outcompeting Chinook salmon for food. In Alaska, populations of pink salmon have been increasing. As pink and Chinook salmon feed on some of the same types of prey, such as small fish and squid, the larger population numbers of pink salmon give them an advantage over Chinook salmon when hunting for food. As a result, there is not enough food left for Chinook salmon to survive on.
Warm Ocean Temperatures
Another theory is that warm ocean temperatures caused the decline of Chinook salmon. Biologists noticed a significant decrease in the Chinook salmon numbers after a mass of unusually warm water called “the blob” appeared along the coast of Alaska in 2013. Chinook salmon are cold – water fish, and warm ocean temperatures negatively affect their health. When temperatures are higher than usual, it takes more energy for Chinook salmon to swim, which stresses their bodies, especially their hearts, and threatens their survival.
Predators
A final explanation is that predators, such as sharks, are responsible for the decline of Chinook salmon. In one study, scientists attached satellite tags to a number of wild Chinook salmon in Alaska. Satellite tags are small devices that send out radio signals about the animals’ locations and the surrounding environment. Data from the tags attached to Chinook salmon showed that the majority of the salmon ended up being eaten by sharks and other predators.
学术写作：
Instructions
Your professor is teaching a class on sociology. Write a post responding to the professor’s question.
In your response you should:
- Express and support your opinion.
- Make a contribution to the discussion in your own words.
An effective response will contain at least 100 words.
Doctor Diaz
We have read studies that explain the negative impact of social media on both children and adults. Many believe that social media will remain widely used in the future, since it is both popular and useful in some contexts. However, due to the problems it poses, it should be regulated in some way. In your opinion, should governments regulate social media platforms or should social media companies regulate their platforms?
Andrew
I believe social media companies should regulate themselves. There are plenty of social media platforms on the market, so the competition is tough. For example, to appeal to parents, a social media platform could publicize that they have stringent regulations for children’s use of the platform. In this way, it could attract more users who care about children’s safety.
Claire
Social media companies should be taking an active role in combating the negative effects, but that is not really happening. I hear many stories of false information spreading around, sometimes causing irreparable damage to people’s reputations. Therefore, the government should put stricter regulations on social media companies, and they should be punished
