1. What does Jacob ask Amy to do?
A.Enjoy the flowers. | B.Provide help. | C.Grow flowers. |
A.Every day. | B.Every two days. | C.Every three days. |
A.They lack water. | B.They lack sunshine. | C.Their leaves turn yellow. |
A.Water flowers in time. | B.Learn about growing flowers. | C.Grow flowers with Amy. |
2 . When lightning caused fires around California’s Big Basin Redwoods State Park north of Santa Cruz in August 2020, the fire spread quickly. Mild fires strike coastal redwood (红杉) forests about every decade. The giant trees resist burning thanks to the bark (树皮), up to about 30 centimetres thick at the base, which contains acids. Their branches and needles are normally beyond the reach of flames. But this time flames shot through the top of 100-metre-tall trees, burning the needles. “It was shocking,” says Drew Peltier, a tree expert at Northern Arizona University. “It really seemed like most of the trees were going to die.”
Yet many of them lived. In a paper published yesterday in Nature Plants, Peltier and his colleagues help explain why: The survivors use long-held energy reserves—sugars that had been made from sunlight decades earlier—and poured them into buds (芽) that had been lying dormant (休眠的) under the bar k for centuries.
“This is one of those papers that challenges our previous knowledge on tree growth,” says Adrian Rocha, an ecosystem ecologist at the University of Notre Dame. “It is amazing to learn that carbon taken up decades ago can be used to sustain its growth into the future.” The findings suggest redwoods have the tools to cope with big fires driven by climate change, Rocha says. Still, it’s unclear whether the trees could cope with the regular infernos that might occur under a warmer climate environment.
The fire in 2020 was so intense that even the top branches of many trees burned and their ability to photosynthesize (光合作用) went up in smoke along with their pine needles. Trees photosynthesize to create sugars and other carbohydrates (碳水化合物), which provide the energy they need to grow and repair tissue. Trees do store some of this energy, which they can call on during a drought or after a fire. Although the redwoods have sprouted (长出) new growth, Peltier and other forest experts wonder how the trees will cope with far less energy from photosynthesis, given that it will be years before they grow as many needles as they had before the fire. “They’re alive, but I would be a little concerned for them in the future.”
1. What’s special about this big fire for coastal redwood forests in 2020?A.It burnt the top of the trees. | B.It was very close to the last fire. |
C.It resisted burning effectively. | D.It caused relatively minor damage. |
A.Sugars protected their barks. | B.Energy reserves promoted the growth of buds. |
C.They got used to hot climate. | D.They took in much carbon to resist fire. |
A.Unpredictable disasters. | B.Changeable climate. |
C.Terrible environment. | D.Uncontrollable fires. |
A.Their tissues can’t be repaired. | B.They can’t save energy anymore. |
C.Their energy saved is not sufficient. | D.They grow too slowly. |
3 . Cork is a light brown material harvested from the cork oak tree. Cork is lightweight, strong and resistant to water.
The cork oak tree is native to the western Mediterranean coast of Europe.
Because cork oak trees are not killed during harvest, they can live for as long as 200 years. Also, used cork products can be recycled and used again. This makes cork a valuable renewable resource.
A.After drying, the cork is ready to be cut. |
B.Harvests only happen once every nine years. |
C.Cork has even found a use in making rockets. |
D.It is best known for keeping liquids from spilling. |
E.Cork can be shined and used to cover floors and walls. |
F.The largest cork oak forests in the world are in Portugal. |
G.The wine industry has been a major supporter of cork production. |
1. How many people died in a landslide in 2003?
A.About two hundred. | B.Over one thousand. | C.About two thousand. |
A.Growing grass. | B.Cutting down trees. | C.Growing population. |
A.Growing more forests. |
B.Chopping down the old forests. |
C.Getting busy in protecting our country. |
A.From not enough water. |
B.From not enough sun. |
C.From not enough plant food. |
6 . There are a number of animals that give off light in some way-including several kinds of insects and fish. Some kinds of mushrooms give off light, too. But most plants don’t give out light. Now, scientists are working to change that.
When a living thing gives off light, it’s called bioluminescence(生物发光). Fireflies are a well-known example of bioluminescence. Though less well-known, many mushrooms are also bioluminescent. These bioluminescent creatures light up thanks to the chemicals called luciferins(荧光素)inside their bodies. Luciferins cause a chemical reaction that can give off light.
Plants don’t naturally have luciferins, so there are no naturally bioluminescent plants. But that hasn’t stopped scientists from trying to create them. In the past, scientists have created plants that made less bright by adding DNA from shining objects. Scientists have also created plants that can give off light by adding luciferins to plants. But it only works as long as the chemicals last. In 2017, a team was able to cause a plant to give off light for about four hours.
Now, researchers at a Russian company have come up with a new method of creating shining plants. By adding certain parts of the DNA from shining mushrooms to ordinary tobacco plants, the researchers were able to create plants that could make their own luciferins. The scientists reported that the light was about 10 times brighter than in earlier shining plants.
The researchers believe that shining plants could help scientists learn more about the way plants work. For example, the moving patterns or waves of light in the plants may show activities in plants that normally can’t be seen. The shining also helps reveal how plants may be affected by things around them. For example, the plants gave off much more light strongly when a ripe banana skin was nearby. But the researchers don’t think the plants will just be used for science. They think many people may want shining plants for their beauty. So they are working with a company to develop shining plants for sale.
1. What phenomenon does the author describe in paragraph 1?A.Most animals hate giving off light. |
B.Many plants give off light through scientists’ efforts. |
C.Animals give off light to protect themselves. |
D.It’s hard to find plants that give out light. |
A.It gives off lots of heat to warm itself. |
B.It has chemical reactions inside its body. |
C.It lacks energy due to chemical reactions. |
D.It informs other fireflies of the danger. |
A.By showing numbers. | B.By making a comparison. |
C.By providing examples. | D.By making a summary. |
A.Human development results in less shining plants |
B.Scientists manage to create shining plants |
C.People’s lifestyles are reflected in shining plants |
D.Geography determines the types of shining plants |
1. What is Akira Miyawaki?
A.A scientist. | B.A professor. | C.An officer. |
A.Producing more oxygen. |
B.Dealing with climate change. |
C.Attracting different kinds of animals. |
A.It helped communities build 100 forests. |
B.It taught people to grow their own mini forests. |
C.It educated kids about tiny forests. |
A.Mini forests are inspired by a French scientist. |
B.Miyawaki has planted more than 1,000 forests in Japan. |
C.Planting mini forests has become popular in Europe. |
8 . Keeping plants at home is a healthy and comfortable way of life. The following houseplants can create a most beautiful piece of green for your home.
Bird’s Nest Fern (蕨)The bird’s nest fern is a good choice for anyone with a house that wouldn’t support sun-loving species. It’s a hardy fern variety adapting to living on forest floors, where the air tends to be cool and damp. It likes to be misted as well, but this doesn’t always mean you need a misting bottle—spraying (喷洒) it in the sink or hanging it near a shower often works as well.
Chinese Money PlantThis is a flowering species that might be most appropriate for experienced plant gardeners looking for a new challenge. It prefers a moderate amount of indirect light, and tends to dry out slightly between watering sessions. It produces new plants easily without any input, directly from its root system. These can coexist in the same pot for a time.
Resurrection PlantThis native of the Mexican desert has adapted to surviving in extreme drought by curling (蜷缩) into a ball and remaining in seemingly lifeless state for years, if necessary. In this form, it can be transported by the wind across the dry landscape to areas with water. It will revive within hours in a shallow bowl of water, unfolding and transforming into a fresh and green moss (苔藓).
Snake PlantThis is a striking houseplant that can be an especially good option for new plant owners who you might not trust to keep a plant alive. It grows happily in almost any condition. While it prefers bright light, it doesn’t mind shade or even artificial light. Plus, thanks to its thick, fleshy leaves, it stores water with remarkable efficiency, which makes it survive without water in the earth.
1. What is special about the bird’s nest fern?A.It prefers shade. | B.It is sun-loving. |
C.It tends to grow in the sink. | D.It can return to life after death. |
A.Bird’s nest fern. | B.Chinese money plant. |
C.Resurrection plant. | D.Snake plant. |
A.They demand attentive owners. | B.They are very drought-tolerant. |
C.They will curl for self-protection. | D.They can store water for drought. |
9 . Imagine walking by a maple (枫树) tree that is no taller than a ruler. You may think that this is a special type of miniature tree, but it actually isn’t! Creating a tree like this is a form of art called bonsai. Bonsai are tiny trees grown in small pots. Bonsai can be any kind of tree. They just need to be planted in a small container and cultivated in a way that stunts their growth.
Cultivating, or taking care of, a bonsai tree requires patience and care. Pruning — removing branches, leaves, and roots — is an important part of raising bonsai. It keeps the trees small, and it also controls their shape. Pinching off new buds (嫩芽) and tying wire around branches help create a beautiful design. These processes allow the grower to control what shape the bonsai tree will take as it develops.
People who raise bonsai want their trees to look like they belong in nature. Even though it is contained in a pot, a bonsai tree should look similar to its larger counterpart (相对物,参照物). For example, the bonsai maple should have the same forked branches and vibrant leaves as the full-sized maple. This makes the bonsai a tiny copy of the full-sized maple that towers overhead.
Like other plants, bonsai need water and food from the soil. In order to keep bonsai the proper size, you need to carefully control the amount of water and fertilizer you provide. If you want to grow a bonsai, it is best to start with a species that grows in your area. Most bonsai do best when kept outdoors, so they need to be able to survive the weather. If kept indoors, the bonsai must be placed near a window. Interestingly, with proper care, bonsai can live for a hundred years or more.
1. Why does a bonsai tree need pruning frequently?A.To control its size. |
B.To help it grow well. |
C.To save fertilizer and water. |
D.To create a shape as designed. |
A.One of a larger counterpart. |
B.A tiny copy of the full-sized maple. |
C.One looking like its counterpart in nature. |
D.One with forked branches and vibrant leaver. |
A.To keep the bonsai indoors. |
B.To start with a native species. |
C.To keep bonsai the proper size. |
D.To control the amount of water. |
A.Bonsai — a special hobby |
B.How to be bonsai grower |
C.What does bonsai refer to? |
D.Why is bonsai so popular? |
10 . 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. |