1 . Tips For a Great Fall Garden

A fall garden can be a great place, which allows us to revel (陶醉) in the beauty and abundance of the season. Many gardeners seem to focus on summer so much that the garden can fade during the fall and not live up to its full potential.     1    

Grow annual crops in fall.

    2     When you switch from summer growing to year-round growing, you will beamazed by how much more you are able to grow and by the abundance of your yields. By growing the right crops at the right times, your garden can be incredibly productive.

    3    

Whether for production or for decoration, it is always a good idea to look first at native plants. Plants that are native to your area should always make up a high proportion of the plants you grow. Selecting plenty of native plants that bloom in the fall helps you to boost biodiversity and they look lovely and right at home.

Use and value fall leaves.

When trees drop their colorful leaves, creating a great fall garden means making the most of those leaves as a resource to keep your garden looking good. To make the most of fall leaves, you can use them to protect the soil and overwintering plants, to enrich the soil and fill planters or containers.     4    

Add garden features for year-round enjoyment.

Making a great fall garden is mostly about the plants you choose and the way you choose to garden. But gardens should not be entirely about hard work.     5     Covered seating areas, garden buildings, outdoor heat sources and perhaps outdoor lighting can help you enjoy your garden as much in the fall as you do in the summer.

A．Choose native plants for a diverse fall garden.

B．Make designs for forest gardening on a small scale.

C．To help these gardeners, here are some tips for a great fall garden.

D．Native plants for your area can become shopping lists for a fall garden.

E．You can take steps to ensure you can fully enjoy the space in cooler seasons.

F．You can even take on some arts and crafts projects to enjoy their colors and shapes.

G．In cooler gardens, it is possible to grow year-round if you create an underco ver growing area.

2 . In a new study, researchers found that invasive insects in the United States could kill approximately 1.4 million urban trees by 2050, which would cost over $900 million to replace, reports Vishwam Sankaran for the Independent.

Hot spots predicted to have the most urban tree mortality (死亡率) were Milwaukee, Wisconsin; Chicago, Illinois; and New York, New York. The study, published in the Journal of Applied Ecology, is the first nationwide forecast of street tree mortality from invasive insects.

The emerald ash borer is an invasive beetle native to Asia. It was first detected in 2002 in southeastern Michigan, and experts suspect it was brought into the United States on wood packing material carried on cargo ships or airplanes traveling from Asia. Since then, the bug has been damaging ash trees. In the last two decades since the insect was first detected, numerous trees have been killed in North America.

Data collected from 30,000 communities across the country was used to estimate tree mortality in the next 30 years. The researchers combined this data with a model that predicted the spread of 57 different invasive insect species. Their results show emerald ash borers alone could cause 90% of the estimated 1.4 million tree deaths. Ash borers are already predicted to “kill virtually all ash trees” in over 6,000 urban areas, according to Newsweek.

Less than 25% of 30,000 urban areas in the U.S. are expected to experience 95% of all street-tree mortality, reports Adam Barnes for the Hill. The areas that will experience the most tree loss include cities in the Midwest and East Coast. These locations are expected to have the most tree loss because large numbers of ash trees occupy the streets and parks in these areas, reported the Independent.

When it comes to how to save urban areas from becoming treeless, study author Emma Hudgins, a biologist at McGill University, says, “These results can hopefully provide a cautionary tale against planting a single species of tree throughout entire cities, as has been done with ash trees in North America. Planting various trees provides resilience against pest infestations (侵扰).”

1. What can we know about the emerald ash borer?

A．It is an invasive beetle in Asia.

B．It was first found by the Michigan people.

C．It has killed numerous trees in America.

D．They definitely enter the U.S. by cargo ships or airplanes.

2. What is the fourth paragraph intended to describe?

A．The purpose of the research.	B．The conclusion of the research.
C．The significance of the research.	D．The process and result of the research.

3. What can be inferred from the fifth paragraph?

A．Pest infestations are taking place across the country.

B．The insect’s invasion won’t spread equally in America.

C．Tree loss is the main cause of environmental problems.

D．Ash trees are being removed from many areas in the U.S.

4. What suggestion does Emma Hudgins provide?

A．Getting different types of trees planted.

B．Replacing foreign trees with local ones.

C．Getting more trees planted in more areas.

D．Planting trees resistant to pest infestations.

3 . Scientists have been experimenting with playing sounds to plants since at least the 1960s, during which time they have been exposed to everything from Beethoven to Michael Jackson. Over the years, evidence that this sort of thing can have an effect has been growing. One paper, published in 2018, claimed that an Asian shrub known as the telegraph plant grew substantially larger leaves when exposed to 56 days of Buddhist music — but not if it was exposed to Western pop music or silence. Another, published last year, found that marigolds and sage plants exposed to the noise of traffic from a busy motorway suffered growth difficulty.

Plants have been evolving (进化) alongside the insects that eat them for hundreds of millions of years. With that in mind, Heidi Appel, a botanist now at the University of Houston, and Reginald Cocroft, a biologist at the University of Missouri, wondered if plants might be sensitive to the sounds made by the animals with which they most often interact. They recorded the vibrations made by certain species of caterpillars (毛毛虫) as they chewed on leaves. These vibrations are not powerful enough to produce sound waves in the air. But they are able to travel across leaves and branches, and even to neighbouring plants if their leaves touch.

They then exposed tobacco plant — the plant biologist’s version of the laboratory mouse — to the recorded vibrations while no caterpillars were actually present. Later, they put real caterpillars on the plants to see if exposure had led them to prepare for an insect attack. The results were striking. Leaves that had been exposed had significantly higher levels of defensive chemicals, making them much harder for the caterpillars to eat. Leaves that had not been exposed to vibrations showed no such response. Other sorts of vibration — caused by the wind, for instance, or other insects that do not eat leaves — had no effect.

“Now speakers with the right audio files are more often being used to warn crops to act when insects are detected but not yet widespread,” says Dr. Cocroft. “Unlike chemical pesticides, sound waves leave no dangerous chemicals.”

1. What can we learn about plants from the first paragraph?

A．They may enjoy Western music.	B．They can’t stand Buddhist music.
C．They can react to different sounds.	D．They can make different sounds.

2. What’s the basis for Appel and Cocroft’s research?

A．Plants can make a cry for help.	B．Plants evolve alongside insects.
C．Plants are sensitive to the sounds.	D．Plants have been studied for years.

3. What can we infer about plants from Paragraph 3?

A．They can recongnize harmful vibrations.	B．They look like laboratory mice.
C．They can threaten the caterpillars.	D．They can release poisonous chemicals.

4. What does the last paragraph mainly talk about?

A．Disadvantages of chemical pesticides.	B．Application of the experimental results.
C．Interaction between plants and insects.	D．Warning system of widespread insects.

4 . A new study reveals that trees can communicate and warn each other of danger. “For the first time, researchers have been able to visualize plant-to-plant communication,” said Masatsugu, senior author of the study.

The idea of talking trees started to take root in the 1980s. Two scientists found that damaged trees began producing chemicals that made their leaves unappetizing and indigestible to discourage insects. The trees then sent chemical signals to one another through the air. Over the past four decades, scientists have observed this cell-to-cell communication in more than 30 plant species.

Past research shows plants communicate with their surroundings by releasing chemicals known as volatile (易挥发的) organic compounds. One class of these compounds are released when a plant is injured: green leafy volatiles. These are released by, as the name suggests, pretty much every green plant with leaves, and are produced when a plant experiences physical damage. An example of these compounds is the smell released from fresh-cut grass.

In the new study, Masatsugu and his colleagues manually damaged leaves and placed insects on tomato plants to trigger the release of various green leafy volatiles. After testing many of them, the team found it seemed to increase calcium ions (钙离子) inside cells. The calcium signaling is like a switch to turn on the defense responses from the plants.

With this new understanding, researchers say plants could be immunized against threats and stressors before they even happen. For instance, exposing healthy plants to insect-ridden plants or the associated green leafy volatiles could boost their genetic defenses, so farmers use less pesticides. The revelation could also help make plants more resilient (有复原力的) during a drought, signaling the plants to conserve more water.

1. What does the new research find?

A．Trees can inform other trees of potential threats.	B．Trees can make themselves attractive.
C．Trees will send signals first once damaged.	D．Trees will work together to trick insects.

2. What can be learnt about green leafy volatiles?

A．They defend insects.	B．They kill insects.
C．Some of them can be smelt.	D．Some of them can be seen.

3. How was the study carried out by Masatsugu?

A．By protecting trees from insects.	B．By classifying green leafy volatiles.
C．By increasing calcium ions inside cells.	D．By causing the release of certain chemicals.

4. What aspect of the new study does the last paragraph focus on?

A．Its target.

B．Its process.

C．Its application.

D．Its background.