| A．From not enough water. |
| B．From not enough sun. |
| C．From not enough plant food. |
2 . 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
4 . Most plants you see out in nature are leafy and green, at least for some part of their lives. That’s because they use green pigments, which are called chlorophyll (叶绿素), to harvest energy from sunlight. But the plant Hydnora Africana, doesn’t have leaves or chlorophyll at all.
So, how can it survive? Well, it’s a parasite (寄生), and H Africana attaches itself to other plants’ roots, and begins getting sugars, minerals, and water from its host.
At the same time, the parasite grows a root system, living completely underground, until it’s ready to reproduce. At which point, it grows one of the strangest looking flowers in the world. When the flower’s mature, it breaks the soil from beneath and reaches out in order to be pollinated (授粉).
But just as this plant doesn’t look like the normal flower, it doesn’t smell like one either. It gives out a smell like a rotting (腐烂) animal . The smell attracts insects and flies looking for a delicious meal. But when they get inside the flower and find no tasty treat, they can’t get back out again.
There’s a sort of room inside the flower, and the top of the room closes behind the insects. The walls of the flower are also slippery, making escape even more difficult.
Over the course of about a day, the flower’s male organs mature, and the insects get coated in pollen. And at the end of this transformation, the inside of the plant gets less slippery, and the chamber opens, allowing the insects and flies to escape.
At that point, attracted by a new rotting smell, they might just find another H Africana flower and pollinate it as they fall inside.
1. Why is chlorophyll so important to plants?| A．Chlorophyll gives plants green color. |
| B．Chlorophyll helps leaves to grow. |
| C．Chlorophyll can harvest energy from sunlight. |
| D．Plants cannot survive without Chlorophyll . |
| A．It’s a parasite without roots. |
| B．It gets food through other plants’ root. |
| C．It never grows out of the ground. |
| D．Its flowers smell sweet. |
| A．find tasty treat inside the flower. |
| B．never get out of the flower again. |
| C．get little chance to pollinate successfully. |
| D．escape after being trapped about a day. |
| A．What is a parasite. |
| B．How a parasite to survive. |
| C．How H Africana reproduce. |
| D．Why bad smell is so useful. |
5 . Planting the right seeds(种子)at the right time will not take as lots of efforts as we think. And some vegetables do grow themselves well without paying too much attention. Here are 4 vegetables that are perfect for a backyard garden.
Green beans
There is really only one important rule for planting green beans—don’t plant them too early. They won’t survive a frost. They may also stop producing in the middle of the summer, but if you continue to water them, they will continue to produce once the temperatures start to drop in early fall. The most time-intensive part of growing beans is in the harvest. The more frequently you pick up beans, the more beans it will grow.
Brussels sprouts(抱子甘蓝)
This sweet vegetable can be grown in nearly any home garden with rich sunlight. They have a long growing season compared with other vegetables. Their taste improves if they are covered with frost. However, they can only bear a few days of cold weather, so be sure to harvest them as quickly as possible.
Broccoli(西兰花)
Broccoli is a cool-weather plant that grows best in spring and fall. It can be planted in early spring for a summer harvest, or in late summer to be harvested in fall. If grown in winter, to avoid heavy frost, broccoli can also be grown indoors and moved to the garden when temperatures rise. When growing broccoli, be sure to watch out for pests(害虫).
Peas
Peas are a great choice for new gardeners. All you need is a container that is at least 10 inches deep and something for the plants to climb. They prefer low temperatures, and once the heat of summer hits, pea plants will stop producing. If your garden space is limited, you can pull them up in the summer and replace peas with another crop that likes the heat
1. What can you do to harvest more green beans?| A．Plant them early. | B．Gather them in time. |
| C．Grow them indoors. | D．Avoid watering them in summer. |
| A．It will taste better. | B．It will grow better. |
| C．It will attract pests. | D．It will go bad immediately. |
| A．They can survive frost. | B．They enjoy cool weather. |
| C．They take up a lot of space. | D．They stop growing in summer. |
6 . The earth’s climate is largely controlled by how much of the sun’s light and heat is absorbed and reflected. By absorbing the sun’s heat, trees cool the air.
The interaction of this relationship with an area’s topography (地势), latitude (纬度), and altitude, can create microclimates (微气候), just as trees create microclimates almost any place they are by providing a windbreak (风林) and shade. Think about it: On a hot, sunny day, it’s always cooler beneath a shade tree. A city with more tall trees is cooler in the summer than a similar city with fewer trees, which translates into less energy use and lowers cooling costs. Also, in using less energy, less air pollution is created.
The most important role that rural trees and forests play is taking carbon dioxide out of the atmosphere. The living tissue (组织) of a tree is a storage vault (拱顶) for carbon, which would otherwise contribute to the greenhouse effect and to global climate change. To put it most simply, more trees can decrease the rate of climate change and help us withstand its effects, potentially resulting in less intense storms, fewer infectious diseases, a more stable water supply, and fewer wildfires.
Trees, however, are affected by the effects of climate warming. Areas once too cold to support trees now can, and as forests migrate north, harmful insects that were once held at bay (使不能接近) by winter freezes can do damage to native species. Tropical (热带的) vines called lianas (藤本植物) are now growing faster than the trees they climb, causing trees in the Amazon and other rainforests to die at an alarming rate.
Trees and forests can either be the key to slowing climate change and reducing its effects, or they can become its victims. It’s up to us.
1. Trees are believed to create microclimates in that __________.| A．tress can take in large sum of sunlight |
| B．tress can effectively change the weather |
| C．tress can help us save more money on cooling |
| D．tress can stop the strong wind and supply shade |
| A．more types of trees will be endangered |
| B．some rare forest species will grow faster |
| C．tropical vines find their wonderful world |
| D．some harmful insects will be under control |
| A．Make up. | B．Stand up to. |
| C．Think about. | D．Bring out. |
| A．Greenhouse effect is increasing sharply. |
| B．Climate change does great damage to trees. |
| C．Many native species will be frozen to death. |
| D．Forests and climate change influence each other. |
7 . How to Grow Plants with Little Sun
Some people might think that growing plants without much sun is a difficult, if not impossible, task. However, that is not true.
What type of shade (背阴处) do you have?
The first step is understanding the type of shade you have. This is based on the amount (数量) of time that the sun shines on the area.
• part shade (3-6 hours of direct sun, usually in the morning)
• full shade (less than 3 hours of direct sun)
• deep shade (sunlight rarely, if ever, gets through trees or past structures like buildings)
Buy the right plants
When you know your shade conditions, find plants that suit them.
And don’t forget your gardeners nearby. When walking around a community garden or your neighborhood, take note of plants growing in shady areas. Talk to the gardeners.
Ways to increase light
The gardening expert adds that painting nearby structures white mirrors sunlight. Glass and mirrored objects can also mirror light around the garden. If possible, carefully cut some tree branches (树枝). This lets more sunlight reach the ground.
What to plant?
Search for the low-light plants suitable for your area.
As for pests (害虫), some kinds like shade gardens. But most other pests are less of a problem in low-light conditions.
| A．There are three main types of shade. |
| B．Learn about their successes and failures. |
| C．Do not give up growing plants you can eat. |
| D．Deep shade is the most challenging for gardeners. |
| E．This information is available where plants are sold. |
| F．Note how many hours of direct sunlight reaches the ground. |
| G．There is another good thing about gardens with less sunlight. |
8 . Seen any unseasonably early daffodils（水仙花）showing their faces yet? UK spring flowers are opening nearly a month earlier than they did before the mid-1980s, due to climate change.
That is the conclusion of a study of nearly 420,000 observations of the first flowering date of 406 plants from a UK citizen science project called Nature's Calendar. It has records dating back to 1753 from gardeners and naturalists, as well as bodies such as the UK's Royal Meteorological Society.
UIf Buntgen at the University of Cambridge and his team found that plants were opening their flowers 26 days earlier on average in the years after 1986 than they did before. They picked that year as it was the mid-point in the data set-where they had about the same number of observations before and after-because there were many more recent records than earlier ones.
The analysis included records of all plants, whatever time of year they flower, but most of them(like the daffodils) bloom in spring. “It is likely that the influence of climate change will be greater for spring-flowering plants, where the usual beginning of warmer temperatures that would cause flowering starts earlier,” says a spokesperson for the UK's Royal Horticultural Society.
There was a bigger advance in the dates of the first blooms for smaller plants, with those less than 20 centimeters high flowering an average of 32 days earlier in the years after 1986 than they had historically.
In any year, flower opening times were closely connected with the average temperature of the months from January to April. “If it's warmer, it's an earlier beginning. If it's cooler, it's a later one,” says Buntgen. The average maximum temperature across those four months rose by 1.1℃, comparing the period from 1950 to 1986 with the years after 1986.
“The change could hurt insects, birds and other wildlife that has evolved to sync with（同步）the flowering of certain plants,” says Buntgen.
1. What can we know about the study?| A．It dated back to 1753. |
| B．It was based on a large amount of data. |
| C．It was conducted by gardeners and naturalists. |
| D．It only covered records of plants blooming in spring. |
| A．It was in the middle of the data set. |
| B．It was a memorable day for Ulf Buntgen. |
| C．It was the first year to record flowering date. |
| D．It was in 1986 that spring flowers bloom earlier. |
| A．The influences of flowers’ early blooming. |
| B．Measures to be taken to stop climate change. |
| C．Further study to find the reason for flowers’ early blooming. |
| D．How creatures adapt to the change of flowers’ early blooming. |
| A．In a guidebook. |
| B．In a science fiction. |
| C．In a geography textbook. |
| D．In a science magazine. |
9 . Many gardeners do not begin to grow their plants from seeds. Instead, they buy young plants, also called seedlings or “starts”. These are plants that are grown in a nursery—a place where plants are grown and sold.
Many gardeners buy seedlings in containers for their gardens. Most nursery seedlings are either plants that last for one growing season or vegetables.
The first step is finding a good nursery. A good gardener will ask themselves whether the nursery grows its own plants, or buys them from larger growers.
Make sure the plants have been watered correctly. If not, the seedlings will have a hard time developing. If there are lots of half-dead or dried-out plants, it is often a sign to buy elsewhere.
Next, before buying a grouping of seedlings, feel the soil. In addition to being wet but not flooded, it should not be solid.
Look at the holes at the bottom of the container to see the roots. If the roots are too dense (密度大的), that is a sign not to buy the plant. Look to see if there has been damage from the wind or sun.
When you buy spring plants in cell containers, you should make sure all the plants in the group are healthy. If one out of four plants in a grouping is not healthy, the others might not be far behind.
| A．Damaged plants will take time to repair. |
| B．That is a sign that the soil has been dried out. |
| C．Lastly, always have a plan when buying plants. |
| D．Pay attention to the price when buying spring starts. |
| E．They come in plastic containers holding four to six plants. |
| F．A gardener should also know what kind of plants they are buying. |
| G．Nurseries that grow their own spring starts usually take good care of them. |
10 . About 17 years ago, I became allergic to Delhi's air. My doctors told me that my lung function had gone down to 70 percent. My doctor told me that there were three plants, with which I could grow all the fresh air indoors to keep me healthy.
The three plants are Areca palm, Mother-in-law's Tongue and money plant. Areca palm is a plant which removes CO2 and turns it into oxygen. We need four shoulder-high plants every person. The second plant is Mother-in-law's Tongue. It is called a bedroom plant because it turns CO, into oxygen at night. And we need six to eight waist-high plants every person. The third plant is money plant, and it preferably grows in hydroponics. This particular plant removes some harmful chemicals.
My team and I have tried these plants at our own building in Delhi, which is a 50,000-square-feet, 20-yearold building. And it has close to 1,200 such plants for 300 families. Our studies have found that there is a 42 percent probability of one's blood oxygen going up by one percent if one stays indoors in this building for 10 hours. Our experience also points to an amazing reduction in energy requirements in the building by an outstanding 15 percent. The government has published a study to show that this is the healthiest building in Delhi. And the study has also shown that, compared to other buildings, there is a reduced incidence of headaches by 24 percent.
In my opinion, these studies above are also important for the environment because the world’s energy requirements are expected to grow by 30 percent in the next decade. 40 percent of the world's energy is taken up by buildings currently, and 60 percent of the world's population will be living in buildings in cities with a population of over one million in the next 15 years. And there is a growing preference for living and working in air-conditioned places.
1. What is the function of the first paragraph?| A．To show the results of growing plants. | B．To give the reason for the author's studies. |
| C．To introduce the author's life. | D．To praise the author's doctor. |
| A．CO2. | B．Oxygen. | C．Money plant. | D．Mother-in-law's Tongue. |
| A．The building with the three plants is the healthiest in Delhi |
| B．The possibility of headaches reduces by 40 percent. |
| C．The energy requirements in the building drop by 42 percent. |
| D．People can stay in the building for only 10 hours. |
| A．Complex. | B．Boring. | C．Meaningful. | D．Useless. |
