题干

在“商品—货币—商品”的流通过程中,“商品—货币”阶段的变化“是商品的惊险的跳跃”。这个跳跃如果不成功,摔坏的不是商品,而是商品所有者。这说明

A:货币作为一般等价物在物物交换中起决定作用

B:商品生产者生产的商品就失去了使用价值和价值

C:货币作为商品交换的媒介必须是观念上的货币

D:商品生产者需要生产适销对路、质量上乘的商品

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答案(点此获取答案解析)

D

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阅读理解

     Butterfly gardens can be grown throughout the United States.There is a wide variety of both butterfly­attracting (nectar) plants and host plants covering climate zones throughout the country.Butterfly gardens can range  in size from a few containers placed in a sunny spot to several acres.

     Nectar­producing (产蜜的) plants will attract butterflies to your garden.In order to support a full butterfly life cycle,host plants (for laying eggs and used as a caterpillar food source) must also be present.

     Throughout the country,the general requirements  for butterfly gardening are the same:full sun,nectar source plants,larval (幼虫的)  host plants,a pesticide­free environment,and knowledge of the local butterfly  species.Many butterfly­attracting plants are natives and require little attention,as they are naturally adapted to the region in which they live.

     Butterfly gardens are best planted in spring with younger plants or in fall with mature plants that will become dormant quickly and re­emerge in  spring.It is best not to plant in the heat of summer or the cold of winter.

     One of the most common mistakes in butterfly gardening is planting only one nectar source.Adult butterflies have a very short lifespan.Planting a variety of nectar sources will encourage more butterflies to visit the garden.Planting an adequate supply of host plants gives butterflies a place to lay their eggs,which will successfully hatch (孵化) and result in butterflies that will continue to visit the garden.

     Butterflies typically lay their eggs in late spring and hatch 3-6 days after they are laid.It takes 3-4 weeks for a caterpillar to pupate (化蛹) and 9-14 days to emerge as an adult.

      Good resources for learning more about butterfly gardening include zoos,botanical gardens,butterfly houses,garden centers and nurseries,libraries and the Internet.There are many good websites dedicated to butterflies and butterfly gardening.