1 . On Christmas Eve, a team of reindeer (驯鹿) will help Santa Claus deliver gifts to children all around the world. The reindeer, led by their fearless leader Rudolph, won’t be the only ones doing something special. Back in the highest Arctic, their cousins have a remarkable ability changing their eye color.
During the summer months, when the days are long and the sun is bright, reindeer’s tapetum lucidum (荧光膜), a mirror-like layer at the back of their eye, appears golden, which helps bounce the majority of light off the eyes, effectively acting like a pair of natural sunglasses. As winter comes, and the days become shorter and darker, the tapetum lucidum turns blue to absorb more light, allowing reindeer to improve their night vision and see clear in low light conditions.
With these adaptations, reindeer can adapt and thrive in one of the harshest environments on Earth. Unlike humans, reindeer can see well into the shorter Ultra Violet (UV) range. This UV vision enables them to spot food and predators more effectively in the snowy landscape. Lichens, a key part of their winter diet, absorb UV, so they show up dark against UV-reflecting white snow. Wolf and polar bear fur also absorb UV, so instead of disappearing against snow they pop out in high contrast, allowing reindeer to spot potential threats from a distance.
Reindeer change their eyes by adjusting their tapetum lucidum, which is made of collagen fibers. In winter, the collagen fibers become packed tighter, causing the tapetum lucidum to mainly reflect blue light. This change happens when reindeer dilate their pupils (瞳孔). In summer, the reindeer’s pupils return to a smaller size, which helps reindeer reduce the amount of light entering the eye.
But their unique adaptation may hurt them. Today, the increasing use of artificial lighting, especially during the winter months, poses a potential threat to their sensitive eyes. It can make reindeer lose their way, affecting their ability to survive in their challenging environment. So it is crucial for us to be mindful of our use of electricity and make efforts to minimize light pollution to ensure the well-being and survival of these magnificent creatures.
1. What do we know from paragraph 2?| A．The shape of reindeer’s eyes varies with seasons. |
| B．It is difficult for reindeer to live in low light conditions. |
| C．The tapetum lucidum helps reindeer adapt to seasonal changes. |
| D．Reindeer’s eyes appear golden in winter while blue in summer. |
| A．To help them see clear in dark nights. |
| B．To distinguish food of different colors quickly. |
| C．To protect their eyes from harsh sunlight in summer. |
| D．To better locate food and enemies during snowy days. |
| A．Relax. | B．Expand. | C．Narrow. | D．Hide. |
| A．To call on people to protect reindeer from light pollution. |
| B．To show the reasons for the decline in reindeer population. |
| C．To present humans’ great efforts to reduce artificial lighting. |
| D．To prove reindeer’s strong adaptability to harsh environments. |
2 . We all have an idea about the common types of environmental problems. However, light pollution may be a new term to many of us. But, the fact is that it does affect mankind, other living forms and the environment as a whole.
What is light pollution? It presents all forms of misused man-made light. The obvious cause of light pollution is the use of outdoor lighting products improperly. It can be office lighting, car headlights, station lights, streetlights and many more.
Light pollution is harmful to both animals and plants. Upon studies, it is found that obvious effects are observed in the behaviour of animals that are active at night. Needless to mention, bright light at night makes it difficult for these animals to hunt, wander and perform their regular activities. Light pollution is directly or indirectly responsible for causing several diseases. Its effects are related to disturbance in the physical rhythm (节奏). It contributes to risks of developing cancerous cells. So, it’s nothing less than a threat to human health.
You have already seen the negative effects of light pollution on animals and human health. Apart from this, the actual cost of misused light is about millions of dollars every year. It also leads to the release of greenhouse gases and global warming. After all, coal or gas is used for producing electricity.
While outdoor lighting and using man-made lighting products are part of our modern lifestyle, some simple ways will surely help in reducing light pollution. For example, while installing (安装) outdoor lighting, make sure that they are pointed downwards. Also, use only the required lighting equipment for both home and offices. Believe it or not, many people living in the urban areas cannot view clear sky and stars at night. Let’s contribute our part in reducing the pollution.
1. What can we learn about light pollution?| A．It has little effect on plants. |
| B．It contributes to most cancers. |
| C．It is a negative fruit of light technology. |
| D．It affects animals’ behavior during the day. |
| A．It increases the temperature at night. |
| B．It creates clouds in parts of the Earth. |
| C．It stops the release of greenhouse gases. |
| D．It is related to the burning of coal and gas. |
| A．Forbid the use of outdoor lighting. |
| B．Use clean energy to produce electricity. |
| C．Avoid unnecessary lights at home and offices. |
| D．Reduce money spent on light in urban areas. |
| A．Citizens should be banned to install outdoor lighting. |
| B．Only simple ways can help reduce light pollution. |
| C．There is no clear sky or stars over the urban areas. |
| D．Light pollution needs to be dealt with urgently. |
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