feifei 91

hongyangyan

91. Leachate is a solution, frequently highly contaminated, that develops when water permeates a landifill’s site. If and only if the landfill’s capacity to hold liquids is exceeded does the leachate escape into the environment, generally in unpredictable quantities. A method must be found for disposing of leachate. Most landfill leachate is sent directly to sewage treatment plants, but not all sewage plants are capable of handling the highly contaminated water.

Which one of the following can be inferred from the passage? 
 

(A) The ability to predict the volume of escaping landfill leachate would help solve the disposal problem.

(B) If any water permeates a landfill, leachate will escape into the environment.

(C) No sewage treatment plants are capable of handling leachate. 

(D) Some landfill leachate is sent to sewage treatment plants that are incapable of handling it.

(E) If leachate does not escape from a landfill into the environment, then the landfill’s capacity to hold liquids has not been exceeded.

Why is E the correct answer?

hongyangyan

Please ignore the messy codes above the question. The firefox browser inserted that. I am not sure how to remove.

pianer

'If
and only if the landfill’s capacity to hold liquids is exceeded does the
leachate escape into the environment'

E is basically a rephrase of this sentence, surely it is correct

bebeitts

I would like to ask another quetiosn of feifei

      The population of peregrine falcons declined rapidly during the 1950’s and 1960’s and reached an

all-time low in the early 1970’s. The decline was attributed by scientists to the widespread use of the

pesticide DDT in rural areas.

Which of the following, if true, gives the strongest support to the scientists claim?

(A) DDT was not generally in use in areas devoted to heavy industry.

(B) In the time since the use of DDT was banned in 1972, the population of peregrine falcons has

been steadily increasing.

(C) Peregrine falcons, like other birds of prey, abandon eggs that fallen out of the nest, even if the

eggs remain intact.

(D) Starling, house sparrows, and blue jays-birds the peregrine falcon prey on—were not adversely

affected by DDT in their habitats.

(E) Other birds of prey, such as the osprey, the bald cage, and the brown pclican, are found in the

same area as is the peregrine falcon.

The answer is A why not B?

Thanks

hongyangyan

QUOTE:

以下是引用pianer在2009-12-9 7:15:00的发言：

'If
and only if the landfill’s capacity to hold liquids is exceeded does the
leachate escape into the environment'

E is basically a rephrase of this sentence, surely it is correct

I really don't agree that E is a rephrase of this sentence.

given: if and only if A, then B, we can not conclude that "if not B, then not A".

Please can you explain more on how E can be a rephrase of the sentence mentioned.