求助几道GWD的逻辑

lizzylovely

GWD6-Q17:
Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve metropolitan Boston.

A.    Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve
B.    Concerns about public health have led to the construction of three separate sewer systems between 1876 and 1904 to serve
C.    Concerns about public health have led between 1876 and 1904 to the construction of three separate sewer systems for serving
D.    There were concerns about public health leading to the construction between 1876 and 1904 of three separate sewer systems serving
E.    There were concerns leading between 1876 and 1904 to the construction of three separate sewer systems for serving
这题正确答案是A，但between 1876 and 1904 不是表示一段时间吗，为什么不能用现在完成时。而且of 后面是修饰construction, 难道不应该紧跟其后吗？
GWD6-Q20:
Five years ago, as part of a plan to encourage citizens of Levaska to increase the amount of money they put into savings, Levaska’s government introduced special savings accounts in which up to $3,000 a year can be saved with no tax due on the interest unless money is withdrawn before the account holder reaches the age of sixty-five.  Millions of dollars have accumulated in the special accounts, so the government’s plan is obviously working.
Which of the following, if true, most seriously weakens the argument?

A.    A substantial number of Levaskans have withdrawn at least some of the money they had invested in the special accounts.
B.    Workers in Levaska who already save money in long-term tax-free accounts that are offered through their workplace cannot take advantage of the special savings accounts introduced by the government.
C.    The rate at which interest earned on money deposited in regular savings accounts is taxed depends on the income bracket of the account holder.
D.    Many Levaskans who already had long-term savings have steadily been transferring those savings into the special accounts.
E.    Many of the economists who now claim that the government’s plan has been successful criticized it when it was introduced.
正确答案是D，我不理解，D不是说明special account 很成功吗

GWD6-Q21:
An overwhelming proportion of the most productive employees at SaleCo’s regional offices work not eight hours a day, five days a week, as do other SaleCo employees, but rather ten hours a day, four days a week, with Friday off.  Noting this phenomenon, SaleCo’s president plans to increase overall productivity by keeping the offices closed on Fridays and having all employees work the same schedule—ten hours a day, four days a week.

Which of the following, if true, provides the most reason to doubt that the president’s plan, if implemented, will achieve its stated purpose?

A.    Typically, a SaleCo employee’s least productive hours in the workplace are the early afternoon hours.
B.    None of the employees who work four days a week had volunteered to work that schedule, but all were assigned to it by their supervisors.
C.    Working ten hours a day has allowed the most productive employees to work two hours alone each day in their respective offices relatively undisturbed by fellow employees.
D.    Employees at SaleCo are compensated not on the basis of how many hours a week they work but on the basis of how productive they are during the hours they are at work.
E.    Those SaleCo employees who have a four-day workweek do not take any of their office work to do at home on Fridays.
这题为什么选C呢

judydongxueni

第二个问题，就是说只是saving形式的改变而已，政府没有实质性增加存款

amy虫子

GWD6-Q20:
Five years ago, as part of a plan to encourage citizens of Levaska to increase the amount of money they put into savings, Levaska’s government introduced special savings accounts in which up to $3,000 a year can be saved with no tax due on the interest unless money is withdrawn before the account holder reaches the age of sixty-five.  Millions of dollars have accumulated in the special accounts, so the government’s plan is obviously working.
Which of the following, if true, most seriously weakens the argument?
plan 的目的是增加储蓄
D.    Many Levaskans who already had long-term savings have steadily been transferring those savings into the special accounts. 许多人将已有的长期储蓄里的存款赚到了special account,所以总的储蓄没有增加

GWD6-Q21:
An overwhelming proportion of the most productive employees at SaleCo’s regional offices work not eight hours a day, five days a week, as do other SaleCo employees, but rather ten hours a day, four days a week, with Friday off.  Noting this phenomenon, SaleCo’s president plans to increase overall productivity by keeping the offices closed on Fridays and having all employees work the same schedule—ten hours a day, four days a week.

Which of the following, if true, provides the most reason to doubt that the president’s plan, if implemented, will achieve its stated purpose?
文章说，最有效率的员工一个星期是工作四天，每天工作10小时，其他员工一天工作8小时
C.    Working ten hours a day has allowed the most productive employees to work two hours alone each day in their respective offices relatively undisturbed by fellow employees. 那些工作10小时的有效率的员工有两个小时是不受其他人干扰的， 那如果大家都工作10小时，那就有干扰了，效率就差了

lizzylovely

解释得很清楚，谢谢大家