ChaseDream

标题: Helpppppppp [打印本页]

作者: yunhaoll 时间: 2008-4-29 17:00
标题: Helpppppppp

1 Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species. Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates. Clearly, dropping this restriction would allow the other species to recover. E B

Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
The number of snow geese taken by hunters each year has grown every year for several years.
As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
In the snow goose’s winter habitats, the goose faces no significant natural predation.

Which of the following, if true, most seriously undermines the argument?

?????虽然文章有一句不通，但是大概意思是猎人打snow geese, 打5%以后打猎期就结束了。

觉得B的意思是snow geese 越来越少，可是这又对结论有什么影响呢，怎么削弱了？？

Outbreaks of Rift Valley fever occur irregularly in East Africa, several years apart. When outbreaks do occur, they kill thousands of cattle. A livestock vaccine against the disease exists but is rarely used. It is too expensive for farmers to use routinely, and since it is not effective until a month after vaccination, administering it after an outbreak begins helps very little. Nevertheless, experts predict that use of the vaccine will increase significantly within the next few years.

Which of the following, if true, provides the strongest justification for the experts’ prediction? E

Rift Valley fever is spread by mosquitoes, but each outbreak is so widespread that it is impractical to control it by using insecticides.
When an outbreak of Rift Valley fever occurs, unaffected countries often refuse to import livestock from the countries affected by the outbreak.
It would take less than a month for producers of the vaccine to adjust their production operations to cope with a large increase in demand.
Many cattle farmers in East Africa are nomadic or live in remote villages, and such farmers, who have little access to modern veterinary medicine, are particularly hard hit by outbreaks of Rift Valley fever.
Recently published research has shown that certain identifiable climatic conditions are almost invariably followed, within two to five months, by an outbreak of Rift Valley fever.

E的逻辑是什么呀？？？？

欢迎光临 ChaseDream (https://forum.chasedream.com/)