不好意思，又来问OG 113了

Since the deregulation of airlines, delays at the nation’s increasingly busy airports have increased by 25 percent. To combat this problem, more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines.

Which of the following, if true, casts the most doubt on the effectiveness of the solution proposed above?

(A) The major causes of delays at the nation’s busiest airports are bad weather and overtaxed air traffic control equipment.

(B) Since airline deregulation began, the number of airplanes in operation has increased by 25 percent.

(C) Over 60 percent of the takeoff and landing slots at the nation’s busiest airports are reserved for commercial airlines.

(D) After a small Midwestern airport doubled its allocation of takeoff and landing slots, the number of delays that were reported decreased by 50 percents.

(E) Since deregulation the average length of delay at the nation’s busiest airports has doubled.

为什么不选B啊，总的飞机数多了，那相对延机的比例不就小了嘛

对了，再读一遍的时候，发现是因为“飞机”而不是“航班”所以不对，对不对啊？

谢谢谢谢！！！

题目说：自从航线解禁，延误就增加了25％。为了对付这情况，准备把最忙的机场仅向商业航线开放。

问weaken

A：它因。延误不是因为，解禁后航线数量太多

B：自从航线解禁后，飞机的数量增加了25％。－－飞机数量增加，延误增加，把机场仅向商业航线开放，刚好能解决机场的问题。

C：60％的是包租给商业航线的，现在说是全部给商业航线－－应该能解决问题

D: 无关的机场

E：莫名，无关

 OG的解释“Choice B describes another part of the problem, but says nothing about who uses the additional airplanes”， OG说题目并没有说增加的飞机是什么用途: 如果commercial,如果non-commercial则无关。

我一开始也怀疑B,因为此题太明显的找它因的题型，所以我也认为B是它因，可后来仔细一想，上ETS的当了，B不是它因，而正是推出结论的原因(在增加的飞机是commercial的情况下), 所以支持。之所以很容易认为B是它因，是因为题目开头就说"Since deregulation...."，就想当然deregulation 是本因，其实since deregulation只起到了一个时间状语的作用，而与解决问题的措施"allocaiton more slots to commercial line"相对应的原因,即more commercial filghts才是本因。

所以，B有两个错误：1.什么飞机没说清楚，2.具有极大的支持可能性。

My Approach:

Root Cause: the deregulation of airlines

Issue: delays at the nation’s increasingly busy airports have increased by 25 percent

Solution: (To combat this problem,) more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines. (to tackle the root cause - the deregulation of airlines)

Type of question: weaken.

只要对Root Cause和Solution取非。引入他因：A) The major causes of delays at the nation’s busiest airports are bad weather and overtaxed air traffic control equipment.

请NN多多指教！

I agree with your perfect explanation of B,C

In addition,I think D is wrong because it supports the conclusion

the question asks which one cast doubt on the conclusion