1 . Plastic is everywhere in our modern world. Its toughness makes it an extremely useful material from household items to vehicle parts, but that same toughness makes it hard to break down for recycling or disposal (处理). However, Japanese scientists at the University of Tokyo have developed a new plastic material that can be broken down more easily and can self-heal and remember past shapes.

Based on a kind of plastic called an epoxy resin vitrimer, which is brittle (脆性的), the new plastic boasts a huge range of advantages. Once scratched with a knife, it can completely patch itself up after being heated to 150 ℃ for just 60 seconds. When shaped into the shape of a crane, then flattened, it can fold itself back into the crane shape by being heated up. It does all of this much faster than others of its type.

The new plastic can also break down easier. Even if it’s discarded (丢弃) into the environment, it still poses less of a, problem than other kinds of plastic, which the team demonstrated by placing it in seawater for 30 days. It biodegraded by 25% and released molecules (分子) that are essential food for marine life.

The new plastic is more resistant to breaking. It can also repair itself, and can recover its original memorized shape. It even biodegrades safely in a marine environment, according to Shota Ando, a researcher of the study.

The material can be used in a variety of applications, “Infrastructure materials for roads and bridges are often composed of epoxy resins mixed with compounds such as concrete and carbon,” said Ando. “By using the new plastic, these would be easier to maintain as they would be stronger and healable using heat. Unlike conventional epoxy resins, this new material is hard but stretchable, so it could also be expected to strongly bond materials of different hardness and stretch.”

2 . Landscape architect Kotchakorn Voraakhom has designed a new green roof on the Rangsit Campus of Thammasat University, about 25 miles north of central Bangkok, Thailand. Her imaginative work challenges the common thinking that urbanization has a negative impact on the planet, whether flooding, excess (过度的) energy use, disrupted (扰乱) biodiversity or the heat island effect.

The 236, 806-square-foot structure, which opened in December 2019, includes a flood water management system and Asia’s largest rooftop organic farm. It combines modern landscape architecture with traditional agricultural knowledge, creating a green and friendly environment.

The green roof, containing an H-shaped landscape, looks like a futuristic hill with a brick building beneath it. The hill features a complex pattern of zigzagging terraces (之字形梯田) of planted beds, leading all the way down to the bottom. When rainwater hits the roof, it flows down the zigzags while being absorbed by the soil in the beds, The excess water is directed into four storage ponds — with a capacity of up to 3 million gallons. The process slows down the flow speed of rainwater runoff compared to a normal concrete rooftop. This keeps the area from flooding during heavy rains.

The roof’s terraces are filled with organically grown crops, including a drought tolerant variety of rice, many local vegetables and herbs. The farm can supply the canteens on campus with a large amount of rice, herbs and vegetables a year. The food waste is composted (把……制成堆肥) to fertilize the farm, and water from the storage ponds is used to water plants, creating an entirely localized and circular system.

The farm serves as an outdoor classroom and a source of local jobs, too. Farmers offer workshops on sustainable agriculture and nutrition as part of the university’s sustainability curriculum. “Students and community members are invited to participate in seasonal seeding, harvesting, and so on,” says Voraakhom. “The urban farm is training a new generation of organic farmers with real-world skills. It also promotes a sense of community.”

3 . Scientists have known for years that plants respond to sounds around them. For example, flowers make sweeter nectar (花蜜) to the sound of buzzing bees. But now scientists in Israel have shown that plants also seem to be doing some “talking”.

Professor Lilach Hadany and her team at Tel Aviv University set up microphones to record tomato and tobacco plants under different conditions. Their recordings showed that the plants made ultrasonic (超声波的) sounds.

When the researchers adjusted their recordings so that humans could hear them, they heard sharp clicking noises. Plants clicked hardly at all when they had enough water. But as their soil got drier, they clicked more and more. When scientists cut off a stem (茎) from the plants, the plants also clicked more. But the clicking wasn’t the same as when the plants needed water.

It’s not clear how the plants make the sounds and whether the plants are making the sounds on purpose. But the plants are definitely making noises, and creating much more noises when they’re stressed (not enough water, stem cut off) than when they’re not.

The researchers trained an Artificial Intelligence (AI) system to identify the different kinds of clicking sounds. The system was able to tell the difference between plants that needed water and plants with cuts about 70% of the time. The result suggests that researchers may one day be able to use a plant’s sounds to figure out when it is having trouble, and what trouble it is having. That could be very helpful to farmers.

The new discovery raises many more questions. One important question is: Do plants make sounds to communicate with each other? Other research has shown that plants do seem to communicate in some ways. Plants being attacked by insects send chemicals into the air. Soon, nearby plants (that haven’t been attacked yet) start to make other chemicals that don’t taste good to insects. It’s possible that the ultrasonic sounds could work in a similar way.

With global events like the UN Climate Change Conference     1     (bring) sustainability (可持续性) into public focus, readers are expecting libraries to introduce more sustainable     2     (measure). They try to reduce their electricity usage and buy equipment from providers     3     are struggling to protect the environment. So far,     4     number of the libraries that have already taken steps to reduce their carbon footprint has been increasing.

Devices like monitoring tools can     5     (apply) to identify areas of a library that are frequently unoccupied. The Jean Anderson Morgan Student Center, for example, is taking advantage     6     the tools throughout its library study rooms. Up till now,     7     (significance) improvements have been made in reducing its energy usage. Bulb costs have     8     (obvious) declined, with fewer replacements needed in low occupancy areas.

Fixing automated equipment that runs on minimal electrical power is libraries’ another effort     9     (operate) more sustainably. Sophisticated self-service machines are now able to     10     (simple) the process of loaning and returning books without causing a big increase in a library’s electricity bill.

6 . We all love butterflies. Their beautiful wings attract us, and their presence lights up our garden. Well, that’s our view of butterflies, but have you ever wondered what plants think of them?

The butterflies’ eggs lie on the underside of the leaves. The eggs themselves don’t damage plants. However, upon coming into contact with the eggs, the plants become oversensitive. It means that once a plant recognizes a pest, it will cause death in the contacted plant part. When these dead leaves or partial leaf parts break away from the plant, the eggs on them fall off. Along with the hypersensitivity response, plants also produce something special, which can attract animals to cat the eggs, thus preventing damage in the future.

After the baby butterflies come out of their eggs, the caterpillar (毛虫) stage begins. Most caterpillars feed on the leaves of the plants, damaging some of the plants in your own garden. Incredibly, they are major plant pests that bring about major losses to farmers. The next stage is pupa (蛹). The caterpillars begin their change into an adult. They don’t depend on the energy that the leaves provide. Finally, they become adult butterflies that have wings and move from one plant to the other. They feed on the sweet liquid produced by flowers.

While on their search for food, the butterflies carry pollen (花粉) on their body. They are key pollinators that place pollen from one flower to another in ecosystem. Plants that have flowers will create some special features to draw these pollinators’ attention. Certain plants have flowers giving off smells that can charm butterflies when they are looking for a mate. Some plants even have flat flowers to assist butterflies when landing.

Butterflies aid in pollination during their final adult stage. Thus, they change into beneficial insects to plants. This change makes butterflies an important friend of plants, despite being a hated enemy in previous life cycle stages!

Placed among the busy streets of Washington, D. C. is a large public garden that many Americans have never heard of. The U. S. National Arboretum (植物园) includes     1     collection of flowering plants called azaleas, a field of native plants named ferns, and flowering trees in the dogwood tree area. The garden     2     (establish) by Congress in 1927. It plays a leading part in researching and developing plants like trees, shrubs, flowers, and grasses.

Government scientists are in charge of the 180-hectare area. Their main goal is     3    (strengthen) the U. S. economy by making sure an important kind of agriculture,     4     (call) the nursery industry, continues to perform well. The most recent numbers from the U. S. Department of Agriculture (USDA) show that the ornamental and landscape plant industry creates billions of founds in sales each year.

The arboretum is home to one of the     5     (large) collections of preserved seeds in the world. The National Arboretum Herbarium (植物标本)     6     (house) around 700,000 ex-ample seeds. They include seeds from plants that the USDA considers as     7    (economical) important. Scientists collect many genetically different seeds within a kind of plant from both native and non-native plants. The reason     8     collecting that data is that scientists protect plants from harmful situations like climate change, changed environments, or other new and possible risks.

While the scientists do their work, the public     9     (explore) plants is free to visit the arboretum. Though many people may not know it, the arboretum has had a hand in developing a number of plants     10     are part of American landscaping.