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by smagish » Mon Jul 30, 2012 10:23 pm
The work of mathematician Roger Penrose in the early 1970s, on the geometry of
what are called aperiodic tiles, turned out to describe the architecture of a
previously unknown class of crystals.
(A) what are called aperiodic tiles, turned out to describe
(B) what is called aperiodic tiles, describes
(C) aperiodic tiles, describing
(D) so-called aperiodic tiles, describe
(E) aperiodic tiles, it turned out to describe


My take was B but the OA is A
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by Kasia@EconomistGMAT » Tue Jul 31, 2012 1:23 am
Answer B is incorrect because the verb should agree with "aperiodic tiles" and thus it should be plural. Also this answer omits "turned out to be" and it changes the meaning of the original sentence.

Answer C is stylistically flawed because it does not convey the same meaning as the original sentence.

Answer D is incorrect because the verb "describe" should be in agreement with the noun "work."

Answer E is incorrect because "it" is used unnecessarily and incorrectly.
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by sanrisenew » Tue Jul 31, 2012 3:07 am
Answer B omits "turned out to be" so does A.
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by Lifetron » Tue Jul 31, 2012 8:01 am
B is wrong coz of the tense use. 'Is' should be 'are'.

Describe is wrong in D and E. 'Work' is singular. Should be 'Describes'. However, 'Describe' in 'Turned out to describe' is correct. Since you can't have 'turned out to describes'

C is wrong coz of 'describing', it requires something more.

Structure: <Gerund> -----, <Clause>.

So, Answer is A
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