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. |
2 . A lot of health care are connected with being around trees.
They also do a great deal of good for the environment by reducing air pollution and taking in carbon dioxide from the atmosphere.
A tree’s ability to take in carbon dioxide is especially useful when the tree.is in cities or towns, where there are too many industrial activities. For the study, the researchers used laser scanning methods to take their own carbon readings of trees from the ground as well as the air.
They determined that Camden had a median carton density (浓度) of around 55 tons of carbon per hectare (t/ha). Greener areas of the borough, like Highgate Cemetery, had a carbon density of 380 t/ha — levels that are typically seen in rainforests.
So what exactly does this mean? Trees could help cool the atmosphere by removing carbon dioxide from the air. However, some climate scientists argue that it’s more complicated (复杂的) than that.
| A．We need to protect the ones we already have. |
| B．Global warming is happening at a faster rate than ever. |
| C．These benefits aren’t just felt in the countryside, either. |
| D．For comparison, major cities in the US have a carbon density of 7.7. |
| E．They have been known to reduce people’s stress and improve overall mental health. |
| F．Then they compared their findings with the data from the UK Environment Agency. |
| G．They think the impact of tree-planting activities today may not be seen for many years. |
3 . You’ll only find cherry blossoms in a handful of countries.
Called sakura in Japan, the cherry blossoms of Yoshino and Kyoto are world-famous. Tourists flock to the country each spring to try their hand at a centuries-old activity “flower viewing”. You don’t have to fly to Japan to see them, though. In the US, the cherry blossoms of Washington, D.C., New York City, Philadelphia, St. Louis, Seattle, San Francisco, and Boston are all beautiful in their own way. The flowers can also be viewed in many European and Asian countries, as well as Brazil and Australia in the southern hemisphere.
There are hundreds of cherry tree varieties.
Japan in particular is home to hundreds of types of cherry trees -possibly more than 600.Some types bear fruit, while others don’t. The flowers of many trees change from dark pink to light pink to white throughout the different stages of blossoming, while others progress from greenish yellow to white to pink. One variety, called Kanzan, was bred to have “double blossoms” — or up to28 petals (花瓣) on each flower, compared to the Yoshino tree’s five petals.
You can get arrested for picking a cherry blossom in Washington, D. C.
Resist the urge to take a cherry blossom home with you as a souvenir. In D.C. at least, breaking off a blossom or branch is viewed as destruction of federal property. Those who break this rule could receive a citation (传票), or worse, be arrested. It goes without saying that it’s also illegal to climb the trees. If they sustain damage to their branches, they will never be able to grow new blossom on that particular branch again.
Both the blossoms and leaves are edible.
In Japan, no part of the cherry blossom tree pes to waste. The preserved leaves are used as edible mochi wrappers (a rice cake filled with sweet bean paste), and a number of seasonal snacks feature sakura as a key ingredient Sakura-flavored versions of Pepsi, Coke, tea, and even Starbucks lattes are all popular drinks. You can also find Kit Kats and Pocky snack sticks that taste like sakura.
They were the inspiration behind a record-setting LEGO sculpture.
Legoland Japan, a theme park in Nagoya, set a Guinness World Record in 2018 for the largest LEGO brick cherry blossom tree ever made. The trees stood 14 feet tall, weighed over 7000 pounds, and consisted of more than 800,000 LEGO bricks.
1. In which country can’t you see cherry blossoms according to the passage?| A．America. | B．China. | C．Germany. | D．Egypt |
| A．Climbing cherry trees is tolerable in Washington. | B．Sakura-flavored snacks and drinks are welcomed. |
| C．Kanzan sakura is better than Yoshino sakura. | D．The largest cherry blossom tree grows in Japan. |
| A．A passionate environmentalist. | B．An ecological researcher. |
| C．A student interested in plants. | D．A tourist in Japan |
| A．From not enough water. |
| B．From not enough sun. |
| C．From not enough plant food. |
5 . It’s breathtaking to watch the delicate spring wildflowers come out from their blanket of leaves, bloom, develop and disperse (传播) fruit, all in a matter of a few short days or weeks.
Although they look fragile, these are tough little plants, each focusing its efforts on spreading its species. They have evolved to have a wide range of flower structures and colors, some with fragrances, attracting many different insect species to assist them in pollination (授粉).
There is one strategy (策略) that a surprising number of spring blooming native plants have evolved in common: seed dispersal by ants. As many as thirty percent of the spring flowering plant species in the forests of eastern North America have evolved to take advantage of this situation to benefit themselves. These species have evolved to provide food attached to their seeds to encourage ants to disperse those seeds. This food, called an elaiosome, is a specialized fat body whose chemical composition more closely matches that of the insects that ants prefer than it does that of a seed.
When a fruit opens to disperse its seeds, the elaiosomes are an instant attraction for ants. They take the seed with its attached elaiosome back to their nests for consumption there, but they just eat the elaiosome, their preferred food, and dispose of the seed on their trash pile. This tends to be an environment that is rich in nutrients, and will benefit the growth of the new plant. Just to make sure the ants don’t eat the seeds in addition to the elaiosome, some plant species have hard seed coatings that ants can’t really bite through.
This evolutionary adaptation is somewhat similar to the strategy of plants that have evolved to surround their seeds with fleshy fruits to attract birds to assist them with seed dispersal. Given the fact that there are fewer birds available in early spring to help with seed dispersal, it makes sense that the early blooming plants evolved to partner instead with the ants for this service.
Did you ever wonder how your Spring Beauty managed to pop up in new locations in your lawn or garden? Thank an ant!
1. How many methods do wildflowers have to attract animals according to the text?| A．Two. | B．Three. | C．Four. | D．Five. |
| A．It’s hard to digest. | B．It’s impossible for ants to resist. |
| C．It makes the earth rich in nutrients. | D．It’s often thrown into the trash pile. |
| A．Ants are creative and hardworking. |
| B．Ants are better at dispersing than birds. |
| C．The birds in the early year are not enough. |
| D．The birds are not interested in their fleshy fruits. |
| A．Thank Ants for Wildflowers |
| B．Wildflowers Discover Their Treasures |
| C．New Species of Wildflowers are Found |
| D．Ants Are Superheroes Protecting Environment |
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
1. Why is the baobab tree thought to be strange-looking?
| A．Its trunk sometimes measures more than ten metres in diameter. |
| B．Its trunk is thicker at the top than at the bottom. |
| C．Its branches near the top are longer than those near the ground. |
| A．Its leaves. | B．Its trunk. | C．Its skin of the tree. |
| A．Its empty trunk can be used by people to build everything. |
| B．Its flowers can turn into a kind of cucumber. |
| C．Its leaves and branches can keep the rain water cool and clean. |
| A．The baobab—unusual but useful. |
| B．The baobab—a tree that people can make good use of. |
| C．The baobab—a strange tree that can make ropes. |
| A．Bring flowers. | B．Take a pot plant. |
| C．Buy postcards. | D．Send fruits. |
9 . Sunflowers have increasingly become popular on social media. People enjoy the bright yellow flowers and take pictures of themselves in bright fields of sunflowers, which are called “sunflower selfies.”
Actually, it is easy to grow your own sunflowers. Here are some instructions.
Do you want to start growing sunflowers from seeds?
Then, plant each seed into soil apart. Keep the soil wet, but not too wet, until the seeds begin to grow. During the growth process, you should water regularly the plants. When they grow up, it is best to put up some shelves to protect the plants from strong winds.
When seeds will start coming out of the head, it is time for harvest. Cut the flowers off and put them into a bag or container. In this way, the seeds will not fall out. Then remove the seeds by rubbing flowers with your hands or a hard brush over a container.
Finally, you’d better select those full seeds for food.
| A．Equally attractive is the delicious taste. |
| B．Sunflower seeds may be eaten cooked or uncooked. |
| C．You can also tie the plants to something tall for support. |
| D．Some kinds of sunflowers can grow up to three meters tall. |
| E．It is important to loosen the soil before the seeds are planted. |
| F．Put the selected seeds in room-temperature water for 2-8 hours. |
| G．They will develop long roots that work their way deep into the ground. |
1. Why must trees be planted according to the talk?
| A．To improve farms. | B．To replace desert. | C．To fight climate change. |
| A．4%. | B．13%. | C．17%. |
| A．Farmers’. | B．Scientists’. | C．Business experts’. |
