题型:阅读理解 题类:模拟题 难易度:普通
黑龙江省哈尔滨市哈三中2019届高三英语第三次模拟考试试卷
Hacking isn't just for computers and smartphones, According to a study published last week in the journal Science, scientists have found a way to hack a plant's genes in order to make it use sunlight more quickly. Someday, the results could increase the amount of food produced around the world.
Photosynthesis(光合作用)is the word used to describe how plants use sunlight, water, and carbon dioxide to make their own food. Scientists who conducted the new study say this is a very slow process. Plants use less than 1 percent of the energy available to therm. But by hacking a plant's genes, the scientists were able to increase the amount of leaf growth on plants between 14 and 20 percent.
"Specifically, scientists hacked the plant's protective system. Normally, this system is activated when a plant gets too much sunlight, "said scientist Krishna Niyogi, co-author of the study. When the plant senses the light, it gets rid of extra energy and creates more leaves. When the plant is in shade, the protective system is turned off, but the process is slow.
Stephen Long is the lead author of the study. He compared a plant's protective system to light-adjusting glasses. When a person wears the glasses outside during the day, the lenses(镜片)darken and lighten depending on how sunny it is. Plants do the same thing, he said. But in plants the adjustment can take anywhere from 10 minutes to an hour. This makes it hard for plants to get the right amount of sunlight needed to create food.
The new study sped up the process. By changing the plant's genes, the protective system turned on and off more quickly than normal. As a result, leaf growth on the plants scientists used in the study increased. Leaf growth in two plants increased by 20 percent, while leaf growth on a third plant increased by 14 percent. Scientists conducted the study on tobacco plants. But they think the genetic changes will produce the same results in corn and rice.
Experience the newly opened Grand Canyon West Skywalk in Colorado.Departing from Grand Canyon's South Rim by Airplane to Grand Canyon's West Rim,you will land and take a ground tour to the Skywalk! Walk on air for 70 feet over the edge of Grand Canyon West.
This Skywalk has been open since March 28,2007.Daily visitor-ship to the Skywalk has been over 4000 people. Please be patient to enjoy your moment on the Skywalk.
After you have experienced the one and only Grand Canyon Skywalk Glass Bridge from where you can enjoy the scenery better,you will return to the Grand Canyon West airport and take your Airplane for a flight back to the South Rim of the Canyon.This is a tour never to be forgotten as you will have walked on air over the Grand Canyon.
Tour Itinerary
Tour Time | 5.7 Hours | The Grand Canyon Skywalk |
Flight from Grand Canyon South Rim to Grand Canyon West | 1 Hour | Experience a bird's-eye view of the Grand Canyon as you make your way to Grand Canyon West. |
Light Lunch at Guano Point at Grand Canyon West | 2 Hour | You'll be taken by bus to Guano Point with breathtaking views of the western part of the Grand Canyon where the Colorado River makes its way into Lake Mood.Every table for lunch has a view. |
Walk on the World-famous Skywalk | 1.5 Hour | Finally you'll board your bus to Eagle Point,home of the Grand Canyon Skywalk.Now it is time for you to walk on air for 70 feet over the Grand Canyon. |
Flight Back to Grand Canyon South Rim | 1.2 Hour | After time on the Skywalk,you'll return to the Grand Canyon West Airport and return to Grand Canyon South Rim in time for dinner and sunset. |
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