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A few milliamps of electricity can cause plants to increase synthesis of chemicals. These compounds often also have a pharmacological (related to medicine) or commercial value, so the trick could be used to help increase yields of commercially useful biologicals. Artemisinic acid, from sweet wormwood, for example, is used in malarial medications, and shikonin (紫草素), from the purple gromwell plant, is used against skin infections.
Researchers have long known that stressing plants can force them to take defensive action, often ramping up the production of protective chemicals that, for example, make them more resistant to insect attack. It has become common practice to stress such plants into increasing their yields. This is usually clone using physical stress elicitors (诱导子), including bits of the micro-organisms that normally attack the plants, or irritants made from metallic compounds such as copper chloride. These are effective, but they come at a cost. Most elicitors a
A. Reactions to the electric stress lead to more chemical yields.
B. Yields of commercially useful biologicals are increased.
C. Using electricity to elicit chemical production is very exciting.
D. Using electricity has a negative effect on plant growth.

[单项选择]

A few milliamps of electricity can cause plants to increase synthesis of chemicals. These compounds often also have a pharmacological (related to medicine) or commercial value, so the trick could be used to help increase yields of commercially useful biologicals. Artemisinic acid, from sweet wormwood, for example, is used in malarial medications, and shikonin (紫草素), from the purple gromwell plant, is used against skin infections.
Researchers have long known that stressing plants can force them to take defensive action, often ramping up the production of protective chemicals that, for example, make them more resistant to insect attack. It has become common practice to stress such plants into increasing their yields. This is usually clone using physical stress elicitors (诱导子), including bits of the micro-organisms that normally attack the plants, or irritants made from metallic compounds such as copper chloride. These are effective, but they come at a cost. Most elicitors a
A. take precautions against skin infections
B. increase production of useful biologicals
C. increase pharmacological and commercial value
D. make plants more resistant to attack

[单项选择]Wine buffs are like art collectors. Few can tell the difference between a well-made fake and the real thing. Yet whereas counterfeit art has been around for centuries, wine forgery is relatively new. It started in the late 1970s when the prices of the best wines—especially those from Bordeaux—shot up. Today, with demand from China fuelling a remarkable boom, counterfeiting is rife. By some estimates 5% of fine wines sold at auction or on the secondary market are not what they claim to be on the label.
The simplest technique is to slap the label of a 1982 Chàteau Lafite (one of the most prized recent vintages) onto a bottle of 1975 Lafite (a less divine year). Another trick is to bribe the sommelier of a fancy restaurant to pass on empty bottles that once held expensive wine, along with the corks. These can be refilled with cheaper wine, recorked and resealed. Empty Lafite and Latour bottles are sold on eBay for several hundred euros.
The margins are fruity. A great wine may c
A. It is difficult to distinguish the well-made fakes from the real ones.
B. The sharp rise in prices of wine is the main reason for the appearance of counterfeits in the late 1970s.
C. The increasing consumption of best wine in China has stimulated counterfeits to become more popular.
D. Counterfeits have successfully entered the second market and even some auctions.

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Most plants can make their own food from sunlight, (1) some have discovered that stealing is an easier way to live. Thousands of plant species get by (2) photosynthesizing, and over 400 of these species seem to live by pilfering sugars from an underground (3) of fungi(真菌). But in (4) a handful of these plants has this modus operandi been traced to a relatively obscure fungus. To find out how (5) are (6) , mycologist Martin Bidartondo of the University of California at Berkeley and his team looked in their roots. What they found were (7) of a common type of fungus, so (8) that it is found in nearly 70 percent of all plants. The presence of this common fungus in these plants not only (9) at how they survive, says Bidartondo, but also suggests that many ordinary plants might prosper from a little looting, too.
Plants have (10) relations to get what they need to survive. Normal, (11)
A. floor
B. level
C. ground
D. layer