1 . On the occasional clear-frost autumn night, I was hiking through the dark forest with my GMO wolf. Yes, my best friend is a genetically modified organism (转基因生物), deliberate selection has produced the blunt-toothed, small-pawed wonder that walks by my side.
Our world is changing rapidly. In the last five decades, global population has fully doubled, with 3.7 billion hungry mouths added to our planet. During this same time span, the amount of land suitable for agriculture has increased by only 5%. Miraculously, this did not result in the great global famine (饥荒) one might have predicted.
How do scientists modify a plant so that it makes more food than its parents did? We could treat each harvest like a litter of wolf pups and select only plants bearing the fattest, richest seeds for the next season. This was the method our ancestors used to engineer rice, com and wheat from the wild grasses they encountered.
During my childhood, advances in genetic technologies allowed scientists to identify and clone the genes responsible for repressing stem growth, leading to shorter, stronger stalks that could bear more seed — the high-yield crops that feed us today. The 21st century has brought with it a marvelous new set of high-tech tools with which to further quicken the process of artificial selection. Plant geneticists can now directly edit out or edit in sections of DNA using molecular scissors.We can minimize a plant’s weaknesses while adding to its strengths, and we don’t have to wait for seasons to pass to test the result.
It is the transformative potential of these techniques to quickly supply the next-generation crops required for upcoming climate change that has led me to believe in the safety and function of GMO plants in agricultural products. We need more GMO research to feed the world that we are creating.
I love the quiet forest that stands between my lab and my home. But I know that as a scientist, I am responsible first to humanity. We must feed, shelter and nurture one another as our first priority, and to do so, we must take advantage of our best technologies, which have always included some type of genetic modification. We must continue as before, nourishing the future as we feed ourselves, and each year plant only the very best of what we have collectively engineered. I keep the faith of my ancestors each night when I walk through the forest to my lab, and my GMO wolf does the same when she guards my way home.
1. Why does the author mention the wolf in the 1st paragraph?| A．To advise people to keep wolves as pets. |
| B．To persuade readers to welcome the new technology. |
| C．To change people’s attitude towards wolves. |
| D．To introduce a technology used to humans’ advantage. |
| A．GMO technology will help weatherproof future crops. |
| B．With GMO technology, famine has been eliminated. |
| C．Artificial selections make high-yield plants possible. |
| D．The author believes technology should contribute to future generations. |
| A．It takes scientists seasons to know whether their selection is correct. |
| B．One way for ancestors to change a plant was to clone some genes. |
| C．Modem techniques help speed up the artificial selection by altering DNA. |
| D．The general public show strong faith in GMO plants, n |
| A．GMO Technology — Turning Wolves into the Best Pets |
| B．Engineered Food — Feeding Future Generations |
| C．Engineered Food — To Be or Not To Be |
| D．GMO Technology — A Driving Force in World Peace |
2 . Against the supposition that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.
This finding suggests that taking steps to prevent northern forest to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.
This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.
Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧）levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.
“We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.
1. According to the new findings, taking steps to prevent northern forest fires may _______.| A．result in a warming climate |
| B．cause the forest fires to occur more frequently |
| C．lead to a longer fire season |
| D．protect the forests and the environment there |
| A．large amounts of greenhouse gases enter the atmosphere |
| B．the levels of ozone which is a type of oxygen increase |
| C．snow on the ground mirrors more sunlight back into space |
| D．ashes from the fire fall on the ice surface and take in more radiation from the sun |
| A．analyze all aspects of how northern fires influence climate |
| B．indicate that forest fires will pollute the atmosphere |
| C．suggest that people should take measures to protect the environment |
| D．suggest that the fires will speed up climate warming |
| A．released | B．absorbed |
| C．created | D．distributed |
| A．warm the climate as the supposition goes |
| B．allow more snow to reflect more sunlight into space and thus cool the climate |
| C．destroy large areas of forests and pollute the far-off sea ice |
| D．help to gain more energy rather than release more energy |
