A
As far back as the age of dinosaurs millions of years ago, turtles (海龟) wandered around the Earth.Even nowadays it is generally assumed that turtles are the world's steadiest creature.
However, a new research shows 61 percent of the 356 species of turtles are already threatened or no longer exist.The destruction of their homes, disease, climate change and other reasons have caused their population to drop sharply.In a new study published in the journal BioScience, a team of scientists from various institutions claim that turtles are one of the most threatened among the major vertebrate (脊椎动物) groups.
This could, the authors say, have serious consequences for the ecology.Turtles contribute to the health of many environments, including desert, wetland, freshwater and marine ecosystems, and the decline may lead to bad effects on other species, including humans, they explain.Whit Gibbons, senior author and professor at the University of Georgia's Savannah River Ecology Laboratory, says in a statement that the intention of the study is to inform people about the vital ecological roles of turtles.
One of the important qualities of turtles is how diverse they are when it comes to food.This allows them to have a major impact on food webs of their homes all over the world.In some areas, the density (密度) of the turtle population makes them an important part of the ecosystem.With their gathering, other species that feed on them and their eggs are sure to have a large pool of food.
For plants, turtles are also extremely important as they distribute the seeds of many plant species.When they eat, some seeds are not destroyed by the digestive process and instead make their way out of the animals' body.Some turtles are the main dispersal (传播) agents of certain plants and their seeds.
These are only a few yet very vital roles that turtles play in the ecological landscape.Unfortunately, many species are in serious decline and in danger of disappearing completely.
语篇解读：本文是一篇说明文。文章说明了海龟的数量急剧下降，这对生态系统产生了不利影响。
1．What does the new study aim to do?
A．To save the grand vertebrate groups on earth.
B．To warn people of turtles' terrible situation.
C．To make the importance of turtles' roles known.
D．To claim turtles may be related to dinosaurs.
解析：选C 细节理解题。根据第三段的“the intention of the study is to inform people about the vital ecological roles of turtles”可知，这个研究的目的是让人们了解海龟在生态系统中的重要作用。故选C。
2．How might the disappearance of turtles influence certain plants?
A．Speed up these plants' disappearing.
B．Put an end to these plants' seed spreading.
C．Allow more seeds to grow into plants.
D．Give these plants no chance of survival.
解析：选A 推理判断题。根据第五段中的“they distribute the seeds of many plant species”可知，海龟是很多植物种类的传播媒介。由此可推知，海龟的消失也可能加速这些植物的灭绝。故选A。
3．What can be a suitable title for the text?
A．Turtles Are Sure to Stop Existing
B．The Ecology Will Change with Turtles
C．Decline of Turtles Threatens the World
D．Turtles' Dying Out Worldwide Matters a Lot
解析：选D 标题归纳题。通读全文可知，作者介绍了目前海龟数量大范围减少的状况以及海龟的存在对生态系统的重要作用，故选D。
