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. |
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【推荐1】Most of us learn how to ride a bike during childhood. But as we grow older, many of us stop riding and put those once-beloved bikes in storage. Years later, when we discover these relics and hop on, it’s as if we never stopped biking.
This is surprising because our memories let us down in so many other instances. So how is it that we can ride a bicycle when we haven’t done so in years?
As it turns out, different types of memories are stored in distinct regions of our brains. Long-term memory is divided into two types: declarative and procedural.
There are two types of declarative memory. Memories of experiences such as the day we started school are called episodic memory(情景记忆). This type of recall is our interpretation of an episode or event that occurred. Factual knowledge, on the other hand, such as the capital of France, is part of semantic memory(语义记忆). These two types of declarative memory content have one thing in common—you are aware of the knowledge and can communicate the memories to others.
Skills such as playing an instrument or riding a bicycle are, however, based on a separate system, called procedural memory, which is responsible for performance.
One of the most famous studies showing the separate memory systems was that of an epileptic(癫痫病患者) named Henry Molaison (H. M.). In the 1950s he underwent the removal of portions of his brain. After the operation doctors found that many of H. M.’s memories of the time before the operation were also erased.
In one test, researchers asked H. M. to trace a five-pointed star on a sheet of paper while only looking at it and his hand in a mirror—meaning the image was reversed. Although H. M.’s hand-eye coordination(协调) skills improved over the several days he performed this task, he never remembered performing it. This meant that he could develop new procedural, but not declarative, memories.
So simple sequences of movements we internalize, even far in the past, are typically preserved for a lifetime. It’s “just like riding a bicycle.”
1. Why riding a bicycle is mentioned in the first paragraph?| A．To introduce the topic. | B．To provide an example. |
| C．To support an argument. | D．To make comparisons. |
| A．Short-term memory. | B．Declarative memory. |
| C．Semantic memory. | D．Procedural memory. |
| A．Brain injury tends to erase people’s all past memories. |
| B．H. M. couldn’t develop new memories after the operation. |
| C．Declarative knowledge is stable and will last long. |
| D．Procedural memory contents aren’t easily forgotten. |
| A．Why don’t we forget how to ride a bike? |
| B．Learn to ride a bike for once and for all |
| C．Is there a memory that never lets us down? |
| D．Where are memories stored in our brains? |
【推荐2】German physicist Albert Einstein is one of the most famous scientists of all time, the personification of genius and the subject of a whole industry of scholarship. In The Einsteinian Revolution, two experts on Einstein’s life and his theory of relativity— Israeli physicist Hanoch Gutfreund and German historian of science Jürgen Renn— offer an original and penetrating (犀利的) analysis of Einstein’s revolutionary contributions to physics and our view of the physical world.
For the first time ever, by setting Einstein’s work in the long course of the evolution of scientific knowledge, Gutfr eund and Renn discover the popular misconception of Einstein as an unconventional scientific genius who single-handedly created modern physics—and by pure thought alone.
As a large part of the book explains, Einstein typically argued that science progresses through steady evolution, not through revolutionary breaks with the past. He saw his theory of relativity not as something from scratch, but a natural extension of the classical physics developed by pioneers such as Italian astronomer Galileo Galilei and English physicist Isaac Newton in the sixteenth and seventeenth centuries, as well as nineteenth-century physicists.
The authors highlight how classical physics cannot be separated cleanly from modern Einsteinian physics. The book also includes substantial sections on Polish astronomer Nicolaus Copernicus and Galileo whose methods inspired Einstein. When Einstein considered himself as standing on their shoulders, he meant that, without their contributions, he would not have formulated (阐述) the theory of relativity.
The Einsteinian Revolution is an important and thought-provoking contribution to the scholarly literature on Einstein and his surprising scientific creativity between 1905 and 1925. Gutfreund and Renn might not have given the final answer as to why Einstein, of all people, revolutionized physics in the way that he did. But they argue in fascinating detail that, to understand his genius, one must take into account not just the earlier history of physics but also the history of knowledge more broadly. Although not always an easy read, the book will interest physicists and historians alike.
1. What’s the attitude of Gutfreund and Renn to the popular viewpoint on Einstein?| A．Opposing. | B．Favorable. | C．Ambiguous. | D．Indifferent. |
| A．From nothing. | B．Up to a certain standard. |
| C．By learning from others. | D．With previous knowledge. |
| A．Their ideas were rejected by Einstein. |
| B．Their devotion to physics impressed Einstein. |
| C．Their research contributed to Einstein’s success. |
| D．Their hard work deserved the worldwide respect. |
| A．A guidebook to a course. | B．An introduction to a book. |
| C．An essay on Albert Einstein. | D．A review of physics development. |
【推荐3】Space is a dangerous place, not only because of meteors(流星), but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on the earth. Light gets through, and this is necessary for plants to make the food which we eat. Heat, too, makes our environment suitable to live. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecraft, if they are inside, do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space. The unit of radiation is called “rem”. Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged; the figure of 60 rems has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage a person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will not be discovered until the birth of deformed(畸形的) children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journeys, the Apollo crew accumulated a large amount of rems. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage done by radiation, but no really effective ones have been found so far.
1. According to the first paragraph, the atmosphere is necessary to man because of the following reason EXCEPT________| A．protecting him against the harmful rays from space | B．providing sufficient light for plant growth |
| C．suppling the heat necessary for human survival | D．screening off the falling meteors |
| A．exposure to even tiny amounts of radiation is fatal |
| B．the effect of exposure to radiation is slow in coming |
| C．radiation is avoidable in space exploration |
| D．astronauts in spacesuits needn’t worry about radiation damage |
| A．is insignificant | B．is enormous | C．seems overestimated | D．remains unknown |
| A．the Apollo mission was very successful |
| B．the protection from space radiation is no easy job |
| C．astronauts may possibly have deformed children or grandchildren |
| D．radiation is not a threat to well-protected space explorers |
| A．Space is dangerous only because of meteors. |
| B．Explorers in space have to avoid the damage from radiation |
| C．We have got effective ways to treat illnesses caused by radiation. |
| D．The atmosphere doesn’t screen off radiation |
【推荐1】The connection between people and plants has long been the subject of scientific research. Recent studies have found positive effects. A study conducted in Youngstown, Ohio, for example, discovered that greener areas of the city experienced less crime. In another, employees were shown to be 15% more productive when their workplaces were decorated with houseplants.
The engineers at the Massachusetts Institute of Technology(MIT) have taken it a step further changing the actual composition of plants in order to get them to perform diverse, even unusual functions. These include plants that have sensors printed onto their leaves to show when they’re short of water and a plant that can detect harmful chemicals in groundwater. “We’re thinking about how we can engineer plants to replace functions of the things that we use every day,” explained Michael Strano, a professor of chemical engineering at MIT.
One of his latest projects has been to make plants grow(发光)in experiments using some common vegetables. Strano’s team found that they could create a faint light for three-and-a-half hours. The light, about one-thousandth of the amount needed to read by, is just a start. The technology, Strano said, could one day be used to light the rooms or even to turn tree into self-powered street lamps.
In the future, the team hopes to develop a version of the technology that can be sprayed onto plant leaves in a one-off treatment that would last the plant’s lifetime. The engineers are also trying to develop an on and off “switch” where the glow would fade when exposed to daylight.
Lighting accounts for about 7% of the total electricity consumed in the US. Since lighting is often far removed from the power source(电源)-such as the distance from a power plant to street lamps on a remote highway-a lot of energy is lost during transmission(传输).
Glowing plants could reduce this distance and therefore help save energy.
1. What is the first paragraph mainly about?| A．A new study of different plants. |
| B．A big fall in crime rates. |
| C．Employees from various workplaces. |
| D．Benefits from green plants. |
| A．To detect plants’ lack of water |
| B．To change compositions of plants |
| C．To make the life of plants longer. |
| D．To test chemicals in plants. |
| A．They will speed up energy production. |
| B．They may transmit electricity to the home. |
| C．They might help reduce energy consumption. |
| D．They could take the place of power plants. |
| A．Whether we can grow more glowing plants. |
| B．How we live with glowing plants. |
| C．Whether glowing plants can replace lamps. |
| D．How glowing plants are made pollution-free. |
【推荐2】Scientists have discovered how plants manage to live alongside each other in places that are dark and shady. Plants in the deep darkness of a thick forest, where natural supplies are not very great in amount, won’t attempt to top their neighbors in growth as those in moderate (中度的) shade do. In deep shade conditions, it would be a waste of energy and harmful to survival because green shoots would never be able to top their larger neighbors in growth.
So how do plants prevent such growth in deep shade conditions? The secret lies in the clocks inside them, say scientists from the John Innes Centre and the University of Bristol.
They have discovered that when plants notice deep shade, this changes the expression of genes in certain parts of the circadian clock (昼夜节律时钟) — the internal daily time r found in plants and other living things. These clock components perform an additional role in preventing plants from lengthening and over topping neighbors.
The work identifies a previously unknown role of the circadian clock in controlling plant development, and the findings may have possible effects on both natural plant populations and crops. Professor Antony Dodd of the John Innes Centre said, “The biological clock of plants plays a big part in their development and fitness. This work casts new light on a new role of the circadian clock in adapting plants to competition with other plants in their environments.” “It also gives us new insights into how plants adapt to very deep shade, where resources are very limited,” said Professor Kerry Franklin at the University of Bristol.
This work provides evidence for the stability of the circadian clock in stressful environments, and information that may be useful in developing new generations of crops in a challenging climate.
1. What do plants normally do in moderate shade?| A．Struggle to preserve energy. | B．Compete for very limited resources. |
| C．Try to outgrow their neighbors. | D．Depend on each other to survive. |
| A．By changing their gene expression. |
| B．By making them realize light change. |
| C．By helping them adapt to the darkness. |
| D．By controlling their growth in deep shade. |
| A．The circadian clock’s role in plant development remains unknown. |
| B．Plants’ living environments are very competitive. |
| C．The circadian clock affects plants’ adaptability to survival competition. |
| D．Plants can adapt to very deep shade where resources are very limited. |
| A．To share a new discovery about plants. |
| B．To introduce the role of the circadian clock. |
| C．To compare plants living in certain conditions. |
| D．To explain plants’ secret of living in forests. |
【推荐3】In Australia, plenty of wild things can bite or sting(刺伤) you. Strangely enough, one of them is a tree. Now scientists have figured out what makes the tree’s sting so bad.
The rainforests of eastern Australia are home to a stinging tree known as Dendrocnide. Many people call it the gympie-gympie tree—a name given to the tree by native Australians. It’s covered with sharp, needle-like hairs that carry poison. If you touch a gympie-gympie tree, you won’t forget it anytime soon. The pain can stay with you for hours, days or weeks. In some cases, it’s been reported to stay for months.
Scientists have long looked for the source of this powerful sting. Now researchers at the University of Queensland have discovered what makes this stinging plant so painful. After carefully studying different kinds of gympie-gympie trees, the scientists were able to separate out different chemicals that the trees produce. This allowed them to identify a group of chemicals that they believed was responsible for the pain.
The researchers created artificial versions of these chemicals, which they call “gympietides”. Sure enough, when the scientists injected mice with gympietides, the mice licked(舔) at the places where they’d been injected, indicating that they hurt in those places. When the scientists studied the way gympietides were built, they found that they formed a knot-like shape. The shape makes the chemicals very stable, which helps explain why the pain stays so long.
The knot-like shape of the gympietides was similar to the shape of poisons produced by poisonous spiders and cone snails. The scientists were surprised to see three very different kinds of life all using similar poisons. Spiders and cone snails carry poisons because they catch food by stinging other creatures. It’s not clear how stinging helps the gympie-gympie tree.
Though the tree’s sting may stop some animals from eating it, it doesn’t stop all animals. Beetles and pademelons (small relatives of the kangaroo) are able to eat the plant without trouble.
1. Why is a touch on the stinging tree unforgettable?| A．Because it has so unusual an appearance. | B．Because it is extremely rare in existence. |
| C．Because touching it creates a quite strange feeling. | D．Because the pain caused by it doesn’t go away quickly. |
| A．How it produces poisons. | B．What poisons it produces. |
| C．How it benefits from the sting. | D．The consequences of its sting. |
| A．It produces the same poisons as spiders. | B．Poisonous as it is, it also has natural enemies. |
| C．Animals are wise enough to stay away from it. | D．Only one chemical in it causes pain to the toucher. |
| A．Scientists Discover Stinging Tree's Secret | B．Caution: Stinging Tree Can Bite and Poison You |
| C．Scientists Discover a Strange Species in Australia | D．Effective Ways to Avoid Being Hurt by Stinging Tree |
