《2024年5年高考3年模拟高二英语选择性必修第一册外研版》

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主题语境:植物的能源消耗语篇类型:说明文难易度:★★☆建议用时:8 min (2024陕西西安蓝田期中)
　　
Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night.This solves the problem of how to portion out(分配)energy reserves during the night so that the plant can keep growing yet not risk burning off all its stored energy.
　　While the sun shines，plants perform phottosynthesis(光合作用).In this process,the plants change sunlight,water and carbon dioxide into stored energy in the form of long chains of sugar,called starch(淀粉).At night,the plants burn this stored starch to fuel continued growth.
　　“The calculations are precise so that plants prevent starvation but also make the most efficient use of their food,”said study co−author Alison Smith.“If the starch store is used too fast,plants will starve and stop growing during the night.If the store is used too slowly,some of it will be wasted."
　　The scientists studied the plant Arabidopsis,which is regarded as a model plant for experiments.To give the plants some math tests,the biologists let night arrive unexpectedly early or late for them.
　　
During one of the exams,they shut off the lights on the plants early that had been grown with twelve−hour days and nights.Putting them into darkness after only an eight−hour day meant they didn't have time to store as much starch as usual.And this forced the plants to adjust their normal nightly rhythm.
　　
Amazingly,even after this day length trick,the plants did very well in their exams and ended up with just five percent of starch left over at the end of the night.They had neither starved,nor stored starch that could have been used to fuel more growth.
　　The authors suggested that similar biological calculators may explain how a migratory bird,the little stint,can make a five−thousand−kilometer journey to their summer habitat in the Arctic and arrive with enough fat reserves to survive only approximatelly half a day more,on average.
　　The results of the study were publlished in eLife.
5.What can we learn from the passage?
　
A.Plants use little energy during the day.　　　　B.Plants usually stop growing at night.
　
C.Plants waste a lot of energy at night.　　　　　D.Plants store starch during the day.
6.What did the scientists do when studying Arabidopsis?
　
A.They changed the plant's light conditions.　　B.They provided the plant with more starch.
　
C.They tried to keep the plant's natural rhythm.D.They attached a biological calculator to the plant.
7.How about the experimental plants when the morning arrived?
　
A.They nearly died of lack of food.　　　　　　B.They used most of their stored energy.
　
C.They began to regulatte their food store.　　　D.They stored enough starch for the next day.
8.What can we learn about the little stintt?
　
A.They may have a system to control energy consSumption.
　
B.They often die during their long and difficult journey.
　
C.They leave the Arctic in summer every year.
　
D.They are unable to calculate the distances.

答案： 5.D 6.A 7.B 8.A