2022 年 06 月大学英语四级考试真题（第 1 套）

Questions __26__ to __35__ are based on the following passage.

You might think of your teeth as tools, like built-in knives and forks, but if they are mere tools, why do they feel pain and wouldn't it be better if they could just __26__ under any condition? In spite of our __27__ discomfort, it turns out there's a good reason our teeth are so sensitive. Tooth pain is a __28__ mechanism that ensures when a tooth is being damaged we'll notice and do something about it.

If we eat something too hot or too cold, or if the tooth is worn down enough where the tissue __29__ is exposed, all of those things cause pain, and then the pain causes the person not to use that tooth to try to protect it a little bit more. So it's really a protective mechanism more than anything else. If teeth didn't feel pain, we might __30__ to use them in situations that damage them, and for humans, damaging __31__ teeth is a problem because, unlike crocodiles, we can't __32__ them.

Teeth have three layers, only one of which-the innermost layer of the tooth-can hurt, as that layer of the tooth __33__ both blood vessels and nerves. Pain is the only feeling to which the nerves in that layer respond. Whereas people with tooth sensitivity may complain, for example, of tooth pain __34__ by heat or cold, the nerves in the inner layer don't sense temperature. Rather, they feel pain, which may be __35__ with, say, drinking something very cold.

Online classes began to be popularized just a few decades ago. They are advertised as a way for adults to finish their education and students to learn the material at their own pace —it is far more compatible for people with busy schedules.

But after being enrolled in an online course last fall semester, I came to realize online classes were merely a means to fulfil course requirements.

First of all, students lack the desire to learn, and they simply complete the assignments to receive credit for a passing grade rather than genuinely engage with the course material.

As online courses tend to have more than 100 students, most of the assignments are short and simple. They are not designed for students to interact with the material in depth but designed to be graded easily to accommodate such a large number of students.

Perhaps the biggest disadvantage of taking an online class is the absence of face-to-face interaction between the teacher and the students. Live sessions are infrequent and are often scheduled during the middle of the day when students have to attend other classes or work. The office hours of the professor may also be during inconvenient times for many students as well. Most interaction with the professor has to be through email which is often impersonal. It is nearly impossible for students to build a relationship with their professor.

There is also little interaction amongst students. It can be harder for students to create study groups and form relationships with their peers.

Online classes also require either a computer or laptop and a reliable internet connection. Not all students have access to these types of resources, whether it is for financial or other reasons, and some students can be put at a disadvantage.

Offering online classes certainly helps students who would otherwise not be able to attend classroom sessions. However, they fail to provide a genuine education with an emphasis on convenience rather than critical thinking. We need restructured online classes in which students can have a learning experience that will actually provide quality education.

In the age of the internet, there's no such thing as a private debate. But is that bad for science? Some scientists have had concerns. When debates in any sector move beyond the halls of universities and government agencies, there's potential for information to be used incorrectly, leading to public confusion; yet, open debate can also promote communication between the scientific community and the public. Recent open debates on scientific research, health, and policy have aroused greater public attention and encouraged more diverse voices. If this trend spurs scientists to agree more quickly about the best solutions to our problems-and at the same time helps the public observe the process of scientific discourse more clearly—then this is good for everyone, including scientists.

A recent debate published in The New York Times discussed the question of how quickly medicine should be developed and produced. Issues such as safety of the product and perception of the public were examined and considered. But some experts worried that such public speculation might lead people to believe that disagreement about the details meant a lack of adequate scientific consensus over the safety and efficiency of modern-day medicine.

The anxiety seems misplaced. Gone are the days of going to a conference and debating scientific issues, and that's good because those gatherings were not diverse enough and excluded many important voices. These days, the public can access debates about science regardless of where they take place.

For many scientists, public debate is a new frontier and it may feel like a place with few restraints or rules? but rather than avoiding such conversations, let the debates be transparent and vigorous, wherever they are held. If the public is to understand that science is an honorably self-correcting process, the idea that science is a fixed set of facts in a textbook needs to be dismissed. With the validity of science coming under attack, there's a need for scientific debates to be perceived as open and true to life. Let everyone see the noisy, messy deliberations that advance science and lead to decisions that benefit us all.