Sentence Correction - Question Pack

[veerocking]

Although improved efficiency in converting harvested trees into wood products may reduce harvest rates,it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand
by increasing supply and lowering prices, thereby boosting
B. in converting harvested trees into wood products may reduce harvest rates, demand will be
stimulated because of increasing supply and lowering prices, which boost
C. of converting harvested trees into wood products may reduce harvest rates, it stimulate demand by
increasing supply and lowering prices, which boosts
D. of harvested trees being converted into wood products may reduce harvest rates, it will stimulate
demand, because it will increase supply and lower prices, thereby boosting
E. when harvested trees are converted into wood products may reduce harvest rates, demand will be
stimulated because of increasing supply and lowering prices, which boost

I want the understand the construction and meaning of the sentence. Also usage of 'which' is not clear.

[crackverbal]

Option A - Correct Answer.
"it" refers to the entire noun phrase "improved efficiency in converting harvested trees into wood products".

the modifier ",thereby boosting consumption" is an effect of the preceding clause "it will stimulate demand ..."

Option B - Incorrect.
"demand will be stimulated ..." - does not make it clear stimulated by what?
"because of increasing supply and lowering prices" - we do not know what causes supply to increase or prices to reduce

Option C - Incorrect.
"increasing supply and lowering prices" is plural. Hence, usage of "boosts" is incorrect.

Option D - Incorrect.
"efficiency of harvested trees + Modifier" - Illogical.
"it will stimulate demand, because it will increase supply and lower prices" - this does not answer the question HOW exactly improved efficiency will stimulate demand? what we can infer from the sentence above is it causes supply to increase. This in turn leads to higher demand. but we do not know HOW the increase in demand will be brought about.

Option E - Incorrect.
"efficiency when harvested trees are converted ..." - does not answer the question efficiency of what/efficiency in doing what?
"demand will be stimulated ..." - by what? Not clear.

[GMATGuruNY]

Although improved efficiency in converting harvested trees into wood products may reduce harvest rates,it will stimulate demand by increasing supply and lowering prices, thereby boosting consumption.

A. in converting harvested trees into wood products may reduce harvest rates, it will stimulate demand
by increasing supply and lowering prices, thereby boosting
B. in converting harvested trees into wood products may reduce harvest rates, demand will be
stimulated because of increasing supply and lowering prices, which boost
C. of converting harvested trees into wood products may reduce harvest rates, it stimulate demand by
increasing supply and lowering prices, which boosts
D. of harvested trees being converted into wood products may reduce harvest rates, it will stimulate
demand, because it will increase supply and lower prices, thereby boosting
E. when harvested trees are converted into wood products may reduce harvest rates, demand will be
stimulated because of increasing supply and lowering prices, which boost

B and E: increasing supply and lowering prices, which boost
Here, it is not crystal clear whether which serves to refer only to lowering prices or to both INCREASING SUPPLY and lowering prices.
Since A avoids this ambiguity and contains no errors, eliminate B and E.

In C, which boosts (which + SINGULAR verb) lacks a singular antecedent.
Eliminate C.

John was impressed by the efficiency of the new machine.
Here, the phrase in blue conveys the following meaning:
The new machine was efficient.
D: the improved efficiency of harvested trees
Here, the conveyed meaning -- that The TREES are efficient -- is nonsensical.
Eliminate D.

The correct answer is A.