Certain groups of Asian snails include both“left-handed”and“right-handed”species,with shells coiling to the left and right,respectively.Some left-handed species have evolved from right-handed ones.Also,researchers found that snail eating snakes in the same habitat have asymmetrical jaws,allowing them to grasp right-handed snail shells more easily.If these snakes ate more right-handed snails over time,this would have given left-handed snails an evolutionary advantage over right-handed snails,with the left-handed snails eventually becoming a new species.Thus,the snakes'asymmetrical jaws probably helped drive the emergence of the left-handed snail species.
Which of the following would,if true,most strengthen the argument that asymmetrical snake jaws helped drive left-handed snail evolution?
A.In one snake species,the snakes with asymmetrical jaws eat snails,while the snakes with symmetrical jaws do not eat snails.
B.Some species of Asian snails contain either all right-handed snails,or all lefthanded snails.
C.Anatomical differences prevent left-handed snails from mating easily with right-handed snails.
D.Some right-handed snails in this habitat have shells with a very narrow opening that helps prevent snakes from extracting the snails from inside their shells.
E.Experiments show that the snail-eating snakes in this habitat fail more often in trying to eat left-handed snails than in trying to eat right-handed snails.
Mall owner:Our mall's occupancy rate is so low that we are barely making a profit.We cannot raise rents because of an unacceptably high risk of losing established tenants.On the other hand,a mall that is fully occupied costs about as much to run as one in which a rental space here and a rental space there stands empty.Clearly,therefore,to increase profits we must sign up new tenants.
Which of the following,if true,most seriously weakens the argument?
A.The mall's operating costs could be cut by consolidating currently rented spaces in such a way that an entire wing of the mall could be closed up.
B.The mall is located in a geographic area in which costs incurred for air-conditioning in the hot summers exceed those incurred for heating in the mid winters by a wide margin.
C.The mall's occupancy rate,though relatively low,has been relatively stable for several years.
D.The mall lost tenants as a result of each of the two major rent increases that have occurred there.
E.None of the mall's established tenants is likely to need additional floor space there in the foreseeable future. 美国研究生留学
to increase profits----must sign up new tenants.
Although the discount stores in Goreville's central shopping district are expected to close within five years as a result of competition from a Spendless discount department store that just opened,those locations will not stay vacant for long.In the five years since the opening of Colson's,a nondiscount department store,a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's.
Which of the following,if true,most seriously weakens the argument?
A.Many customers of Colson's are expected to do less shopping there than they did before the SpendLess store opened.
B.lncreasingly,the stores that have opened in the central shopping district since Colson's opened have been discount stores.
C.At present,the central shopping district has as many stores operating in it as it ever had.
D.Over the course of the next five years,it is expected that Goreville's population will grow at a faster rate than it has for the past several decades.
E.Many stores in the central shopping district sell types of merchandise that are not available at either SpendLess or Colson's.
To improve the long-term savings rate of the citizens of Levaska,the country's legislature decided to implement a plan that allows investors to save up to$1,000 per year in special accounts without paying taxes on the interest earned unless withdrawals are made before the investor reaches age sixty-five.Withdrawals from these accounts prior to age sixty-five would result in the investor's having to pay taxes on all the accumulated interest at the time of withdrawal.
Which of the following,if true,most strongly supports the prediction that the legislature's plan will have its intended effect?
A.The money saved in the tax-free savings accounts will be deposited primarily in those banks and financial institutions that supported the legislation instituting the plan.
B.The majority of people choosing to take advantage of the tax-free savings accounts will withdraw their money prior to age sixty-five.
C.A significant number of the citizens of Levaska will invest in the tax-free savings accounts well before they reach the age of sixty-five.
D.During the ten years prior to implementation of the plan,Levaskans deposited an increasingly smaller percentage of their annual income in long-term savings accounts.
E.People who are not citizens of Levaska are not eligible to invest in the tax-free savings accounts,even if their income is taxable in Levaska.
Letter to the editor:Our city plans to allow major commercial development along the south waterfront and,in so doing,to increase its tax revenue.But,to succeed commercially,the development would inevitably create far more road traffic than the existing roads to the waterfront can handle,causing serious congestion.Providing enough roads or public transportation to the area would cost far more than the city could gain from the increased tax revenue.
Which of the following,if added to the city's plan,would be most likely to help solve the problem the letter describes?
A.Funding construction of new roads to the waterfront with a system of tolls on the new roads to the waterfront
B.Allowing residential development along the waterfront so that there will be waterfront residents who can walk to the commercial development
C.Giving tax breaks to developers of businesses along the waterfront to offset any tax levied on them for construction of roads or public transportation
D.Evaluating the net benefits that the commercial development would bring to the city in terms of improved quality of life for the city's residents rather than in financial terms
E.Allowing commercial development in other city neighborhoods whose roads are not seriously congested with traffic
前提commercial development---increase tax
结论：more roads----costs more
Most of Western music since the Renaissance has been based on a seven-note scale known as the diatonic scale,but when did the scale originate?A fragment of a bone flute excavated at a Neanderthal campsite has four holes,which are spaced in exactly the right way for playing the third through sixth notes of a diatonic scale.The entire flute must surely have had more holes,and the flute was made from a bone that was long enough for these additional holes to have allowed a complete diatonic scale to be played.Therefore,the Neanderthals who made the flute probably used a diatonic musical scale.
In the argument given,the two portions in boldface play which of the following roles?
A.The first introduces evidence to support the main conclusion of the argument;the second is the main conclusion stated in the argument.
B.The first introduces evidence to support the main conclusion of the argument;the second presents a position to which the argument is opposed.
C.The first describes a discovery as undermining the position against which the argument as a whole is directed;the second states the main conclusion of the argument.
D.The first introduces the phenomenon that the argument as a whole seeks to explain;the second presents a position to which the argument is opposed.
E.The first introduces the phenomenon that the argument as a whole seeks to explain;the second gives a reason to rule out one possible explanation.