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发布时间：2006-06-21 20:59     点击：

Time: 55 minutes (including the reading of the directions). Now set your clock　for 55 minutes.　　

　　Question 1-12

　　Orchids are unique in having the most highly developed of all blossoms,in which the usual male and female reproductive organs are fused in a single　structure called the column. The column is designed so that a single pollination　will fertilize hundreds of thousands, and in some

　　cases millions, of seeds, so microscopic and light they are easily carried by　the breeze. Surrounding the column are three sepals and three petals, sometimes　easily recognizable as such, often distorted into gorgeous, weird, but always　functional shapes. The most noticeable of the　petals is called the labellum, or lip. It is often dramatically marked as an　unmistakable landing　strip to attract the specific insect the orchid has chosen as its pollinator.　To lure their pollinators from afar, orchids use appropriately intriguing　shapes, colors, and scents. At least 50 different aromatic compounds have been　analyzed in the orchid family, each blended to attract one, or at most a few,　species of insects or birds. Some orchids even change their scents to interest　different insects at different times.　Once the right insect has been attracted, some orchids present all sorts　of one-way obstacle　courses to make sure it does not leave until pollen has been accurately placed　or removed. By such ingenious adaptations to specific pollinators, orchids have　avoided the hazards of rampant　crossbreeding in the wild, assuring the survival of species as discrete　identities. At the same time　they have made themselves irresistible to collectors.

　　1. What does the passage mainly discuss?

　　(A) Birds

　　(B) Insects

　　(C) Flowers

　　(D) Perfume

　　2 The orchid is unique because of

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