1 . The green and red watermelon is a sweet, refreshing summer snack. But it wasn’t always so sugary or brightly colored. So what did watermelons originally taste and look like, and from where did they come?
The fruit isn’t from the Fertile Crescent of ancient Mesopotamia, as so many other domesticated (家养的) crops are, research shows. Susanne Renner, a scientist, and her colleagues carried out comprehensive genetic sequencing (基因测序) of the domesticated watermelons — the kind you might find on supermarket shelves — along with six wild watermelon species.
“We found the modern genomes (基因组) of the domesticated watermelon are more closely related to the Sudanese wild type than any other that we analyzed,” she said. The Sudanese wild watermelon has some obvious differences from the domesticated version. “The flesh is white and not very sweet, and it’s mainly used as animal feed,” Renner said. Nevertheless, the genetic similarity between the two species led the researchers to conclude that the Sudanese fruit is probably a precursor (前身) to the red and sweet domesticated watermelon.
It’s likely that ancient farmers grew non-bitter varieties of the wild watermelon and thus increased its sweetness over many generations through the domestication process. The red color is probably also thanks to artificial selection, in which farmers likely favored and selectively bred red fruit.
We already knew that the ancient Egyptian king Tutankhamun was buried with watermelon seeds 3,300 years ago, yet that isn’t sufficient proof of a domesticated, sweet watermelon. But then, Renner found an image of a watermelon-like fruit on an ancient Egyptian tomb painting, thought to be more than 4,300 years old. In a separate tomb, another image showed the watermelon cut up in a dish alongside other sweet fruits. This realization, coupled with Renner’s genetic findings, suggests that the watermelon was most likely domesticated around that time either in Egypt or within trading distance of the ancient empire.
“Historically speaking, that’s a very significant finding,” said Hanno Schaefer, a professor of plant biodiversity. “It’s becoming clearer that we’ve greatly neglected the North African region. We’ve focused too much on the Fertile Crescent and we need to invest more resources into studying the agriculture of North Africa.”
1. What can we learn about the Sudanese wild watermelon?| A．It is brightly colored and sugary. |
| B．It is consumed mainly by animals. |
| C．It has no connection with the domesticated type. |
| D．It has more differences than similarities to the domesticated type. |
| A．More resources will be devoted to agriculture research in South Africa. |
| B．The domesticated watermelon has a history of at least four thousand years. |
| C．The domesticated watermelon probably developed from the Sudanese type. |
| D．Few domesticated crops are from the Fertile Crescent of ancient Mesopotamia. |
| A．The history of the Sudanese wild watermelon. |
| B．Where wild watermelons actually come from. |
| C．The characteristics of domesticated watermelons. |
| D．How domesticated watermelons came into being. |
| A．Favorable. | B．Doubtful. | C．Critical. | D．Tolerant. |
Nature’s Lungs
We know that trees are nature’s purifier (净化器): They absorb carbon emissions (碳排放)and release oxygen. But their
According to the study, there are
This may sound like a lot,
Yet, planting trees is still considered the most effective way
| A．Bring flowers. | B．Take a pot plant. |
| C．Buy postcards. | D．Send fruits. |
4 . Many plants and animals live together, and they depend on each other. They are usually very different from their sharing partner, and yet all live easier lives because of each other. It is nature’s idea of sharing.
An example of this is the shark and pilot fish. The pilot fish is a little guy and he would be helpless if he hung around by himself in the great ocean. But his smartness makes up for his size. He cleverly swims along beside the shark and when the shark eats, the pilot fish gets the leftovers. The shark also benefits from this relationship. The pilot fish cleans food scraps (碎屑) and insects from the shark’s skin.
Another example is the sea anemone (海葵) and striped clown fish. The sea anemone looks like a flower but contains poisonous cells. When small fish swim into it, the anemone traps and paralyzes (使麻痹) them. However, the striped clown fish is able to swim into the poisonous anemone without being harmed. To pay for his safety, the clown fish brings food to the anemone. He also guides other fish into the anemone’s deadly trap.
Large mammals such as the ox, antelope and African buffalo form such a relationship with the oxpecker (牛椋鸟). They provide daily meals to the bird that eats insects. The various large mammals act as a restaurant with a varied menu for the oxpecker. What do they get in return from the bird? Free beauty treatments!
Some plants live together in a beneficial relationship. Fungus (菌类) does not have chlorophyll (叶绿素) that plants need to make food. However, the green alga (海藻) does contain chlorophyll. It is, therefore, able to feed the fungus along with itself. But nothing is free! The fungus repays it by protecting the alga. Since it takes in and stores water, it can provide the alga with an unending water supply.
1. Why does the pilot fish swim along beside the shark?| A．Because he likes eating the waste given off by the shark. |
| B．Because he can help the shark get food. |
| C．Because he can get food and protection. |
| D．Because he needs the help of the shark to lead his way. |
| A．paralyzes small fish for him | B．helps him catch other fish |
| C．does some cleaning work | D．warns him of the danger |
| A．Energy and light. | B．Energy and light. |
| C．Light and chlorophyll | D．Chlorophyll and water. |
| A．①→②③④⑤ | B．①→②③→④⑤ |
| C．①②③④→⑤ | D．①②③→④⑤ |
5 . History is filled with many legends of man — eating plants and trees. A man — eating flower was described in the ship’s log of Arkwright. He described this as a large flower with bright petals (花瓣) capable of releasing a special smell that causes the victim to rest on the large petals. Once the victim was in its trap, the flower would close over the victim and digest him alive.
There really are carnivorous plants that can catch and consume small insects, but are there or have there ever been meat-eating plants capable of catching humans, as some explorers have claimed? In this article, we’ll look at one of the most famous man-eating plants in the world and what discoverers and the locals had to say about it — Nicaraguan Vampire Vine.
Found in the swamps (沼泽地) of Nicaragua, local natives refer to this plant as “The Devil’s Snare”. It has been described as an octopus in general appearance. A naturalist called Dunstan spent two years studying the local plant and animal life and made this discovery in a swamp close to Lake Nicaragua. Dunstan was collecting specimens in the area when his dog let out a loud cry.
Unsure whether or not this was due to pain, terror, or a combination of the two, Dunstan rushed to the source of the dog and saw it in a network of roots. These were dark in color, somewhat black, and sent out a sticky gum that had a horrible smell. Dunstan used his knife to cut these tendrils (触须) immediately but was initially unable to do so. Not only were these difficult to cut with just his knife, but they actively fought back.
Dunstan did manage to save his dog, but both suffered injuries during this encounter. Dunstan’s both hands were swelling; his dog was covered in blood. The dog didn’t know which way to go and had trouble walking. Not much else is known about this plant, but the locals do fear it immensely and leave it well alone.
1. How did the man-eating flower attract victims to get close to it?| A．Set up a trap. | B．Show their beautiful appearance. |
| C．Send out a smell. | D．Provide them with petals to rest. |
| A．vegetarian | B．world-famous | C．cruel | D．meat-eating |
| A．It appears together with octopus. |
| B．It could strike back when attacked. |
| C．It had tendrils that could digest dogs. |
| D．It was found by Dunstan in Lake Nicaragua. |
| A．The dog wasn’t seriously hurt in the end. |
| B．Dunstan saved his dog without being hurt. |
| C．People learned more about this plant in detail. |
| D．The locals didn’t dare to get close to the plant. |
6 . Small Container Growing!
Gardeners, or people who grow plants and crops, typically use a part of their own land.
People are gardening on the tops of their homes, in fire escapes and on small outdoor areas for sitting.
Look for small varieties of your favorite vegetables. Even though they are small, the plants will produce a lot! Crops that have the words “little” “mini” and “baby”will be perfect for small containers. Plants that grow towards the sky, and most herbs, also grow well in pots.
There are many things you should take into consideration. After you select the type of crop you want to grow, you must consider the container.
Unlike plants that are grown in the ground, plants grown in containers need more water and fertilizer (肥料). Use deep pots made of metal or plastic to hold water. This can decrease (减少)the amount of water you have to use. Be sure the containers have holes in the bottom.
Most plants that grow food need at least 6 hours of sunlight a day.
With these ideas, a little planning, and the correct plants, your small space can grow a lot of crops!
| A．Push your finger into the soil to check water. |
| B．However, you may have an area with little sunlight. |
| C．But for many people having a bit of land is just a dream. |
| D．These places are best for planting vegetables in containers. |
| E．Depending on what you grow, choose different kinds of fertilizer. |
| F．Besides, consider the type of soil and where your plants will grow. |
| G．Soil from your land is too heavy and may house disease or harmful insects. |
Apples are ready to pick when the skin color deepens and the fruit comes away
To pick an apple, cup it in your hand, lift, and twist gently. It should be separate from
Early season apples are eaten best soon after
Store your apples in a cool but frost-free, dark, well-ventilated place such as a shed or garage. Make sure they don’t touch, or else wrap them in newspaper. Different species store for different lengths of time — keep them separate and use those
8 . It turns out that sunflowers are more than just a pretty face: the ultraviolet (紫外线的) colours of their flowers not only attract pollinators (传粉者), but also help the plant regulate water loss, according to new research.
The yellow sunflower is a familiar sight, but it’s hiding something from the human eye — an ultraviolet bullseye (靶心) pattern, invisible to humans but not to most insects including bees. These bullseye patterns have long been known to improve the attractiveness of flowers to pollinators by increasing their visibility.
“Unexpectedly, we noticed that sunflowers growing in drier climates have flowers with larger ultraviolet bullseyes, and found that those flowers are able to keep water more efficiently. This suggests that these larger ultraviolet bullseyes help plants adapt to these drier environments,” says Dr. Marco Todesco.
Dr. Todesco and his colleagues grew almost 2,000 wild sunflowers of two species at the university in 2016 and 2019. They measured the sunflowers’ ultraviolet patterns, and analyzed the plants’ genes, and found that wild sunflowers from different parts of North America had ultraviolet bullseyes of very different sizes.
Larger floral ultraviolet patterns that have more of these compounds could help reduce the amount of water loss from a sunflower in environments with lower humidity (湿度), preventing too much water loss. In humid, hot environments, smaller ultraviolet patterns would promote the water loss, keeping the plant cool and avoiding overheating.
Sunflowers are planted for various purposes, including sunflower oil production, a roughly $20 billion industry in 2020. This research could help add to knowledge about how to attract pollinators, potentially increasing crop yields, says Dr. Todesco. “This work also helps us understand how sunflowers, and potentially other plants, better adapt to different areas or temperatures, which could be important in a warming climate.”
1. What do we know about sunflowers?| A．They don’t need pollinators. |
| B．Their flowers have special functions. |
| C．Their flowers can drive the insects away. |
| D．They can be grown in extremely cold areas. |
| A．They analyzed 2000 kinds of sunflowers. |
| B．They planted sunflowers to carry out research. |
| C．They travelled to different parts of South America. |
| D．They helped people in North America plant sunflowers. |
| A．Positive. | B．Doubtful. |
| C．Negative. | D．Critical. |
| A．A Hidden Function of Flowers of Sunflowers |
| B．Researchers Found a New Species of Sunflower |
| C．Sunflowers Can Change the Colours of Sunshine |
| D．Ultraviolet Bullseye Patterns Attract More Insects |
9 . Apples are generally red, green, yellow or a combination of the three, but if the right geographical conditions are met, they can grow dark purple, almost black, as well. These apples are called Black Diamond, currently only grown in the mountains of Tibet.
Black Diamond apples get their dark purple color from the geographical conditions of Nyingchi, in Tibet. The 50-hectare (公顷) orchard(果园) set up by Chinese company Dandong Tianluo Sheng Nong E-Commerce Trade Co., Ltd. is 3,100 meters above sea level, making it the perfect place to grow these interesting fruits. The temperature differences between day and night are important, and the fruits get a lot of sunlight and ultraviolet light (紫外线), which causes their skin to go from the deep red to dark purple.
Production at the Nyingchi orchard started in 2015, three years after the trees were planted, but they can only be found in some high-end supermarkets in Beijing, Shanghai, Guangzhou and Shenzhen, and are usually sold in gift package of 6 to 8 fruits. And the price of Black Diamond apples is around 50 yuan per fruit.
Due to the low temperatures, Black Diamond apple trees’ growth rate is much lower than average. While most apple types are fully grown in 2 to 5 years, these trees require no less than 8 years. Furthermore, only about 30% of the orchard’s product meets the standards of color to be sold as high-quality Black Diamond apples.
Black Diamond apples are a mystery, even among experienced apple growers, as there really isn’t much information about them online. Some users of the Growing Fruit forum, for example, think these dark purple apples don’t really exist, while others say that the photos posted online have made the fruits darker than they really are.
1. Which plays a key role in the growth of Black Diamond apples?| A．Much rain. | B．High temperature. |
| C．Much land | D．High altitude |
| A．Their unusual sizes | B．Their limited numbers. |
| C．Their growing conditions. | D．Their high prices. |
| A．Too much heat. | B．Low temperatures. |
| C．Much poor soil. | D．Lack of enough water. |
| A．To tell people’s different ideas of Black Diamond apples. |
| B．To ask readers to learn more about Black Diamond apples. |
| C．To show people know little of Black Diamond apples. |
| D．To prove the information of Black Diamond apples wrong. |
1. What kind of plant can you start with according to the speaker?
| A．Something big. | B．Something easy. | C．Something safe. |
| A．At least six hours. | B．About five hours. | C．Less than four hours. |
| A．To keep it safe from thieves. |
| B．To keep it safe from hungry animals. |
| C．To prevent kids from entering. |
| A．A radio program. | B．A newspaper. | C．A scientific research. |
