Visitors to the zoo usually pity the animals owing to their particular emotional associations(联想). Which animals should be indeed pitied? The first type are those clever and【C1】______developed animals【C2】______lively intelligence and desire for activity can【C3】______no outlet behind the bars of the cage. Those animals living in a free state before【C4】______in the zoo have a strong desire for moving about 【C5】______, but have to turn around repeatedly in their quarters. Owing to this disappointment, foxed and wolves【C6】______in places which are far too small, are among the most【C7】______of all zoo animals. Another sad scene, seldom【C8】______by ordinary zoo visitors, is the【C9】______flying trials of swans(天鹅)at migration(迁徙)time. These creatures, like most other water birds, are generally made unable to fly by the【C10】______of cutting off a tip of the wing bone. 【C11】______such swans in the zoo generally seem happy under【C12】______care and they raise their young without any trouble, at migration time things become【C13】______. The birds never really 【C14】______that they can no longer fly, and repeatedly swim to the【C15】______of the pond so that they can have the whole extent of its surface when trying to【C16】______against the wind. Meanwhile, their loud flying calls can be heard as they try to【C17】______, and again and again the grand preparations end in【C18】______. I do not like seeing those【C19】______water birds in the zoo. The missing tip of one wing and the still sadder picture that the bird makes when it【C20】______its wings hurt me badly. What a truly sorry picture it is.