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In this unlikely place, researchers are putting the seeds from flowering plants and trees in a sleeplike state. Many years from now, other workers will wake the sleeping seeds up to plant them 小题1:they are most needed. These seeds are小题2:the legendary Rip Van Winkle, who fell asleep under a tree and woke up 20 years later.

The small farm, called the Greenbelt Native Plant Center, is part of a global effort to save小题3:(threaten) plants and trees. Around the world, native plants are being crowded out by invasion newcomers. Native plants have less room to grow now小题4:a result of the growth and spread of cities. And global warming is making some places hotter, drier, or different from小题5:native plants are used to.

Experts used to think小题6:possible to protect big-city plants such as American bittersweet because growth space is limited in urban environments. Crowding increases competition between natives and invaders, and the latter often win the battle.

小题7:, scientists have found ways小题8:fighting back. So far, workers at the Greenbelt Native Plant center小题9:(gather) seeds from about 300 of those plants and put them in a sleeplike state. When小题10:(plant) in the future ,these seeds could help restore damaged parkland and forests.