请教完成句子的解题方法

以下是引用joywzy在2003-7-18 23:26:00的发言：
完成句子题，我做不好，哪位XDJM能不能结合这几题讲解一下做完成句子题的思路？谢谢。

11.Which of the following, if true, is the most logical completion of the argument below?
The tax system of the Republic of Grootland encourages borrowing by granting its taxpayers tax relief for interest paid on loans. The system also discourages saving by taxing any interest earned on savings. Nevertheless, it is clear that Grootland's tax system does not consistently favor borrowing over saving, for if it did, there would be no--.
(A) tax relief in Grootland for those portions of a taxpayer's income, if any, hat are set aside to increase that taxpayer's total savings
(B) tax relief in Grootland for the processing fees that taxpayers pay to ending institutions when obtaining certain kinds of loans
(C) tax relief in Grootland for interest that taxpayers are charged on the unpaid balance in credit card accounts
(D) taxes due in Grootland on the cash value of gifts received by taxpayers from banks trying to encourage people to open saving accounts
(E) taxes due in Grootland on the amount that a taxpayer has invested in interest-bearing savings accounts

答案：A，我选了D

21. Which of the following best completes the passage
below?
The unemployment rate in the United States fell
from 7.5 percent in 1981 to 6.9 percent in 1986. It
cannot, however, be properly concluded from these
statistics that the number of unemployed in 1986
was lower than it had been in 1981 because-----.
(A) help-wanted advertisements increased between
1981 and 1986
(B) many of the high-paying industrial jobs avail-
able in 1981 were replaced by low-wage ser-
vice jobs in 1986, resulting in displacements
of hundreds of thousands of workers
(C) in some midwestern industrial states, the unem-
ployment rate was much higher in 1986 than
it had been in 1981
(D) the total available work force, including those
with and without employment, increased
between 1981 and 1986
(E) the average time that employees stay in any
one job dropped during the period 1981
to 1986

答案：D，我不明白work force 是如何说明unemployemnt number 的减少呢？

6. Which of the following best completes the passage below?
“Government” does not exist as an independent entity defining policy. Instead there exists a
group of democratically elected pragmatists sensitive to the electorate, who establish policies that
will result in their own reelection. Therefore, if public policy is hostile to, say, environmental.
concerns, it is not because of governmental perversity but because elected officials believe that —
(A) environmentalists would be extremely difficult to satisfy with any policy, however
environmentally sound
(B) environmental concerns are being accommodated as well as public funds permit
(C) the public is overly anxious about environmental deterioration
(D) the majority of voters vote for certain politicians because of those politicians’ idiosyncratic
positions on policy issues
(E) the majority of voters do not strongly wish for a different policy

答案：E，我选了A，

谢谢。