综合写作：
Everyone sleeps. In fact, not just humans sleep, but most vertebrate animals do as well. However, the purpose of sleep is still debated among biologists. Several theories have been put forward to explain the role of sleep.
One theory says that the main purpose of sleep may be to allow the brain to consolidate and organize the experiences of the day. For example, there is a particular kind of sleep called “rapid eye movement sleep,” or REM sleep. Some studies have shown that people’s performance on tasks that require memory depends on how much REM sleep they get, with more REM sleep resulting in better performance on these memory tasks. Thus, the purpose of sleep may be to facilitate the function of memory.
Another theory is that sleep may allow humans and animals to conserve energy during periods of inactivity. Most animals sleep during periods when their normal activities are not possible. For example, some animals need daylight to see to find their food, so they sleep at night. On the other hand, animals that hunt other animals at night, like owls, sleep during the day. Sleep may help humans and animals conserve energy during these periods of forced inactivity.
A third theory says that the purpose of sleep is to remove toxins from the brain that build up during waking hours. Brain activity, like all metabolic processes, produces toxic chemicals called free radicals, which damage cells. There has been a research study suggesting that the body uses sleep as a kind of recuperation period in order to repair cells that have been damaged by free radicals.
学术写作：
Your professor is teaching a class on business management. Write a post responding to the professor’s question.
In your response, you should do the following:
- Express and support your opinion.
- Make a contribution to the discussion in your own words.
An effective response will contain at least 100 words.
Dr. Diaz
We’ve been discussing employee working arrangements—whether employees should report to an office or work at home. Some businesses require all employees to work in the office. Others choose not to have a physical office and have all employees work from home. In industries where remote work is possible, what is the most important factor for employers to consider when deciding where employees should work, and why?
Claire
I don’t think businesses should allow their employees to work from home, because creating a sense of community and camaraderie among employees is so important for the success of a business, especially if it’s a small business. It is challenging to develop that dynamic when employees are not together physically in the same space.
Andrew
I think the most important thing to consider is the bottom line—keeping company expenses down. For example, requiring all employees to work from home might be the best option from an economic standpoint. Renting office space is expensive, as are the utility bills. Think of how much money a business could save if employees worked from home.
