2024 年 06 月大学英语六级考试真题（第 3 套）

A rainbow is a multi-colored, arc-shaped phenomenon that can appear in the sky. The colors of a rainbow are produced by the reflection and __26__ of light through water droplets (小滴) present in the atmosphere. An observer may __27__ a rainbow to be located either near or far away, but this phenomenon is not actually located at any specific spot. Instead, the appearance of a rainbow depends entirely upon the position of the observer in __28__ to the direction of light. In essence, a rainbow is an __29__ illusion.

Rainbows present a __30__ made up of seven colors in a specific order. In fact, school children in many English-speaking countries are taught to remember the name "Roy G. Biv" as an aid for remembering the colors of a rainbow and their order. "Roy G. Biv" __31__ for: red, orange, yellow, green, blue, indigo, and violet. The outer edge of the rainbow arc is red, while the inner edge is violet.

A rainbow is formed when light (generally sunlight) passes through water droplets __32__ in the atmosphere. The light waves change direction as they pass through the water droplets, resulting in two processes: reflection and refraction (折射). When light reflects off a water droplet, it simply __33__ back in the opposite direction from where it __34__. When light refracts, it takes a different direction. Some individuals refer to refracted light as "bent light waves." A rainbow is formed because white light enters the water droplet, where it bends in several different directions. When these bent light waves reach the other side of the water droplet, they reflect back out of the droplet instead of __35__ passing through the water. Since the white light is separated inside of the water, the refracted light appears as separate colors to the human eye.

Sarcasm and jazz have something surprisingly in common: You know them when you hear them. Sarcasm is mostly understood through tone of voice, which is used to portray the opposite of the literal words. For example, when someone says, "Well, that's exactly what I need right now," their tone can tell you it's not what they need at all.

Most frequently, sarcasm highlights an irritation or is, quite simply, mean.

If you want to be happier and improve your relationships, cut out sarcasm. Why? Because sarcasm is actually hostility disguised as humor.

Despite smiling outwardly, many people who receive sarcastic comments feel put down and often think the sarcastic person is rude, or contemptible. Indeed, it's not surprising that the origin of the word sarcasm derives from the Greek word "sarkazein" which literally means "to tear or strip the flesh off." Hence, it's no wonder that sarcasm is often preceded by the word "cutting" and that it hurts.

What's more, since actions strongly determine thoughts and feelings, when a person consistently acts sarcastically it may only serve to heighten their underlying hostility and insecurity. After all, when you come right down to it, sarcasm can be used as a subtle form of bullying—and most bullies are angry, insecure, or cowardly.

Alternatively, when a person stops voicing negative comments, especially sarcastic ones, they may soon start to feel happier and more self-confident. Also, other people in their life benefit even more because they no longer have to hear the emotionally hurtful language of sarcasm.

Now, I'm not saying all sarcasm is bad. It may just be better used sparingly—like a potent spice in cooking. Too much of the spice, and the dish will be overwhelmed by it. Similarly, an occasional dash of sarcastic wit can spice up a chat and add an element of humor to it. But a big or steady serving of sarcasm will overwhelm the emotional flavor of any conversation and can taste very bitter to its recipient.

So, tone down the sarcasm and work on clever wit instead, which is usually without any hostility and thus more appreciated by those you're communicating with. In essence, sarcasm is easy while true, harmless wit takes talent.

Thus, the main difference between wit and sarcasm is that, as already stated, sarcasm is often hostility disguised as humor. It can be intended to hurt and is often bitter and biting. Witty statements are usually in response to someone's unhelpful remarks or behaviors, and the intent is to untangle and clarify the issue by emphasizing its absurdities. Sarcastic statements are expressed in a cutting manner; witty remarks are delivered with undisguised and harmless humor.

Variability is crucially important for learning new skills. Consider learning how to serve in tennis. Should you always practise serving from the exactly same location on the court, aiming at the same spot? Although practising in more variable conditions will be slower at first, it will likely make you a better tennis player in the end. This is because variability leads to better generalisation of what is learned.

This principle is found in many domains, including speech perception and learning categories. For instance, infants will struggle to learn the category "dog" if they are only exposed to Chihuahuas, instead of many different kinds of dogs.

"There are over ten different names for this basic principle," says Limor Raviv, the senior investigator of a recent study. "Learning from less variable input is often fast, but may fail to generalise to new stimuli."

To identify key patterns and understand the underlying principles of variability effects, Raviv and her colleagues reviewed over 150 studies on variability and generalisation across fields, including computer science, linguistics, categorisation, visual perception and formal education.

The researchers discovered that, across studies, the term variability can refer to at least four different kinds of variability, such as set size and scheduling. "These four kinds of variability have never been directly compared—which means that we currently don't know which is most effective for learning," says Raviv.

The impact of variability depends on whether it is relevant to the task or not. But according to the 'Mr. Miyagi principle', practising seemingly unrelated skills may actually benefit learning of other skills.

But why does variability impact learning and generalisation? One theory is that more variable input can highlight which aspects of a task are relevant and which are not.

Another theory is that greater variability leads to broader generalisations. This is because variability will represent the real world better, including atypical (非典型的) examples.

A third reason has to do with the way memory works: when training is variable, learners are forced to actively reconstruct their memories.

"Understanding the impact of variability is important for literally every aspect of our daily life. Beyond affecting the way we learn language, motor skills, and categories, it even has an impact on our social lives," explains Raviv. "For example, face recognition is affected by whether people grew up in a small community or in a larger community. Exposure to fewer faces during childhood is associated with diminished face memory."

"We hope this work will spark people's curiosity and generate more work on the topic," concludes Raviv."Our paper raises a lot of open questions. Can we find similar effects of variability beyond the brain, for instance, in the immune system?"