[求助]LSAT 26-3-10

hoechst

If a person chooses to walk rather than drive, there is one less vehicle emitting pollution into the air than there would be otherwise. Therefore if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced.
10. Which one of the following, if true, most strengthen the argument?
(A) If automobile passengers who never drive walk instead of ride, there will be fewer vehicles on the road as a result.
(B) Nonmoving running vehicles, on average, emit half as much pollution per second as moving vehicles, but the greater congestion is, the more nonmoving running vehicles there are.
(C) Since different vehicles can pollute at different rates, it is possible for one drive who walks to make a greater contribution to pollution prevention than another driver who walks.
(D) On average, buses pollute more than cars do, but buses usually carry more passengers than cars do.
(E) Those who previously rode as passengers in a vehicle whose driver decides to walk instead of drive might themselves decide to drive.
请问B是如何加强的

Bensontuo

hoechst 发表于 2003-7-17 18:35
If a person chooses to walk rather than drive, there is one less vehicle emitting pollution into the ...

Step 1, Spot the question type : If " one of the answer is could, then the argument of the question must be true or could be true.

Sufficient assumption -

Step 2, Spot the premises and also conclusions of the argument

P1: If A ( person walk and no drive ), then B ( that person would not drive result in less vehicle emitting pollution into the air than there would be otherwise )

C: If C ( A group of each person = people walk when feasible ), then D ( the pollution will be reduced )

Inference -> The core of the argument:

the number of the people choose to walk will decrease the number of the car drove ---> decrease the number of vehicle emitting pollution into the air resulting in the pollution be greatly reduced.

Contrapositive:

If the decreased number of vehicle emitting pollution into the air does not have the pollution be greatly reduced, the number of the people choose to work will not decrease the number of the car drove.

A. we are not talking about people who don't drive ( out of scope )

B. Here is one point that a lot of people might fail to consider. Please do remember that from the original argument " that People would walk whenever it is feasible " ---> pollution be greatly reduced.

What if people walk " after driving their car " and decide to walk " when there is congestion " as one of the feasible way to get to their intended destination ? Apparently, under the scenario like this, the pollution is going to be reduced  vs if they choose continue driving by spending the times waiting until the traffic Jam finished with emitting half as much pollution and full of the pollution from the congestion to their destination.
Also, please also see the contrapostive of the inference above " If the decreased number of vehicle emitting pollution into the air does not have the pollution be greatly reduced, the number of the people choose to walk will not decrease the number of the car drove. "

So, not reduced more than 50 percent could be interpretted as " not " greatly reduced, we do still have cars being droved on the roads and the numbers of cars being droved is still high than the people who chose to walk.

Not the best answer, but compared to other answer, this one apparently is the better.

C. It is also possible that opposite case happened.

D. Without the amount of the passenger loading ratios, bus numbers, and also all the other variables, we can't be certain.

E. Totally weaken, but not strengthen.