阅读 575 评论 0
Journalist:In physics journals,the number of articles reporting the results of experiments involving particle accelerators was lower last year than it had been in previous years.Several of the particle accelerators at major research institutions were out of service the year before last for repairs,so it is likely that the low number of articles was due to the decline in availability of particle accelerators.
Kate:The recent decline in numbers of the Tennessee warbler,a North American songbird that migrates each fall to coffee plantations in South America,is due to the elimination of the dense tree cover that formerly was a feature of most South American coffee plantations.
Scott:The population of the spruce budworm,the warbler's favorite prey in North America,has been dropping.This is a more likely explanation of the warbler's decline.Which of the following,if true,most seriously calls Scott's hypothesis into question?
A.The numbers of the Baltimore oriole,a songbird that does not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler,are declining.
B.The spruce budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.
C.The drop in the population of the spruce budworm is expected to be only temporary.
D.Many Tennessee warblers have begun migrating in the fall to places other than traditional coffee plantations.
E.Although many North American songbirds have declined in numbers,no other species has experienced as great a decline as has the Tennessee warbler.
Teenagers are often priced out of the labor market by the government-mandated minimum-wage level because employers cannot afford to pay that much for extra help.Therefore,if Congress institutes a subminimum wage,a new lower legal wage for teenagers,the teenage unemployment rate,which has been rising since 1960,will no longer increase.
Which of the following,if true,would most weaken the argument above?
A.Since 1960 the teenage unemployment rate has risen when the minimum wage has risen.
B.Since 1960 the teenage unemployment rate has risen even when the minimum wage remained constant.
C.Employers often hire extra help during holiday and warm weather seasons.
D.The teenage unemployment rate rose more quickly in the 1970’s than it did in the 1960’s.
E.The teenage unemployment rate has occasionally declined in the years since 1960.