综合写作：
The narwhal is a medium-sized whale that lives year-round in the Arctic. The species has attracted a lot of scientific attention over the years because it has a perfectly straight 2- to 3-meter-long tusk projecting from its head. Scientists have long wondered what the purpose of the tusk might be. Three possible functions of the tusk have been proposed.
First, the narwhal dwells and hunts within the Arctic Circle, where the sea is often covered with thick pack ice. Like other whales, the narwhal needs air to breathe and cannot stay underwater indefinitely. Eyewitnesses have reported seeing narwhals use their tusks to pierce through the ice sheet from below. The ability to break the ice in this way would give a narwhal access to air whenever it needed to take a breath. That would make it possible for narwhals to freely hunt in waters that are covered with ice.
Second, the tusk could serve as a weapon for fighting with other male narwhals as they compete for territory. Just as rams and male deer charge at one another with their horns or antlers, male narwhals, it seems, may charge or joust with one another. Some observers have claimed to have seen aggressive clashing of tusks between male narwhals.
Third, the surface of the tusk contains many millions of microscopic holes connected to nerves. This configuration suggests that the tusk serves as a sensor that allows the narwhal to detect ocean properties, for example water pressure, temperature, salinity of the water, and even barometric pressure above the water’s surface. The ability to sense such properties would be an important adaptation aiding in the narwhal’s survival.
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:
What should children be learning in school? Many people believe that time in the classroom should be spent acquiring foundational knowledge in subjects like math, reading, science, and history. Others feel that it’s important for a child’s creativity to be nurtured, and thus the school curriculum must include classes in art and music. There’s so much to learn, yet so little time in school to learn it all! What do you think should be included in the curriculum? Why?
Claire:
I agree that traditional subjects like math, science, and reading are important, but so are classes in art and music. Engaging with art and music can help children be more creative and stimulate their imaginations. That, in turn, facilitates critical thinking, which is essential in any curriculum. So, I am in favor of including art and music in the school day.
Paul:
Sure, drawing pictures and listening to music is fun, but children can do that on their own time. The school day is too short as it is, and there is so much foundational knowledge in math, reading, science, and history that children need to learn. It is better to spend classroom time on that foundational knowledge and let kids explore art and music at home.
