综合写作：
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.
学术写作：
教授：对于升职来说的话，哪个因素是最重要的？（教授有罗列一些：员工表现、在公司里待的时间长短、在某个领域的经验、还有领导潜能）
Andrew：在公司待的时间长久（资历深浅）
Claire：工作表现
Doctor Diaz: This week, we are going to discuss companies’ policies for promotion. Companies tend to value different things and set different criteria for determining who deserves a promotion. Criteria for promotion may include employees performance and achievements in their current roles, seniority within the company, years of experience in the field, or even leadership potential. In today’s post, I would like you to discuss which criteria for promotion you see as the most important and explain why.
Andrew: I believe seniority should be the most important criterion for promotion. Rewarding employees who have been with the company for a long time shows that the company values loyalty and dedication. Long-term employees often have a deep understanding of the company’s culture and processes, which can be invaluable.
Claire: I think job performance should be the top criterion for promotions. Rewarding employees for their skills and achievements pushes them to excel in their roles. When people see that their hard work and dedication are recognized, they’re motivated to take the next step in their careers.
