求助三道GWD逻辑填空题！救命！

许楚iris

1.Which of the following most logically completes the argument?

Yorco and Zortech are two corporations that employ large numbers of full-time workers who are paid by the hour.Publicly available records indicate that Yorco employs roughly the same number of such hourly wage workers as Zortech does but spends a far higher total sum per year on wages for such workers.Therefore, hourly wages must be higher, on average, at Yorco than at Zortech, since _____.

A.Zortech spends a higher total sum per year than Yorco does to provide its hourly wage workers with benefits other than wages

B.the work performed by hourly wage workers at Zortech does not require a significantly higher level of skill than the work performed by hourly wage workers at Yorco does

C.the proportion of all company employees who are hourly wage workers is significantly greater at Yorco than it is at Zortech

D.overtime work, which is paid at a substantially higher rate than work done during the regular work week, is rare at both Yorco and Zortech

E.the highest hourly wages paid at Yorco are higher than the highest hourly wages paid at Zortech

这道题我的理解是，Y和Z这两个地方小时工的人数相同，但Y给这些工人的钱多，因此，Y的平均小时工资比Z高，是因为Y的小时工比例比Z高。。
不知道我的理解是不是差太多，真的想不来为什么选D。。

2.Which of the following most logically completes the passage?
Concerned about financial well-being of its elderly citizens, the government of Runagia decided two years ago to increase by 20 percent the government-provided pension paid to all Runagians over 65.  Inflation in the intervening period has been negligible, and the increase has been duly received by all eligible Runagians.  Nevertheless, many of them are no better off financially than they were before the increase, in large part because ________.
A.        They rely entirely on the government pension for their income
B.        Runagian banks are so inefficient that it can take up to three weeks to cash a pension check
C.        They buy goods whose prices tend to rise especially fast in times of inflation
D.        The pension was increased when the number of elderly Runagians below the poverty level reached an all-time high
E.        In Runagia children typically supplement the income of elderly parents, but only by enough to provide them with a comfortable living
这道题我选的是C，答案是E，完全不懂。。
3.Which of the following most logically completes the argument?
Although the pesticide TDX has been widely used by fruit growers since the early 1960's, a regulation in force since 1960 has prohibited sale of fruit on which any TDX residue can be detected. That regulation is about to be replaced by one that allows sale of fruit on which trace amounts of TDX residue are detected. In fact, however, the change will not allow more TDX an fruit than was allowed in the 1960's, because_______.

A.Pre-techniques for detecting TDX residue could detect it only when it was present on fruit in more than the trace amounts allowed by the new regulations.
答案是A，但是我不太懂题中黑体字这句话是什么意思。。trace在这里表示什么意思啊？而且A选项我也没有读懂是什么意思。。麻烦帮翻译一下呗，谢谢啦！！O(∩_∩)O

sdcar2010

Each question asks for a premise to justify the conclusion.  If you understand the conclusion, you simply need to find an answer choice which would enable the conclusion to be drawn.

许楚iris

知道用这个方法来做题，但是还是不是很清楚。。