(A) what are called aperiodic tiles, turned out to describe
is the correct option!!

(B) what is called aperiodic tiles, describes
is illogically refers to the plural subject - aperiodic tables

(C) aperiodic tiles, describing
option C creates a sentence fragment, the subject "the work" has no verb

(D) so-called aperiodic tiles, describe
plural verb "describe" illogically refers to the singular subject "the work"

(E) aperiodic tiles, it turned out to describe
it is ambiguous
_________________

(A) what are called aperiodic tiles, turned out to describe
(B) what is called aperiodic tiles, describes - IS is incorrect because tiles is plural
(C) aperiodic tiles, describing - missing verb
(D) so-called aperiodic tiles, describe - should be singular
(E) aperiodic tiles, it turned out to describe - it is unnecessary

OA is A.

How can singular subject work describe a plural verb describe??

Posted from my mobile device

Hi,

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.

the verb for "the work" is "turned out"

describe is actually "to-describe" to+verbs never act as verbs!

hope this helps
_________________

Strange meaning. "The work turned out to describe". It sounds as if Penrose didnt know what he was working on. Maybe that makes sense, but it seems awkward.

Posted from my mobile device

The answer to the question is mentioned as - A, however, as per the comments in this thread - this option has glaring mistakes with the subject-verb agreement.

My answer was - B, but was marked incorrect

I chose A and this is how I reached that answer.
A lot of people commenting on choice between "what are called" vs "what is called".
I actually started backwards to choose between "turned out to describe/describes/describing/it turned out to describe"
All 5 answers have different wordings so we can have the clear answer by looking at this part.

First, we need "turned out" because we have to show contrast or expression of surprise.
The sentence suggests that it was originally not expected that this work will describe the architecture of crystals.
So we can eliminate B, C, D.
Second, the part after comma on option E reads that, "it turned out to describe."
"It" here does not have clear antecedent and is redundant since the sentence already has "The work" as the subject.
Eliminate E.
Hence, A is our final answer.

I'm confused with " what are called aperiodic tiles ". Option-A
What is the subject for are?

Is this a backward construction?
Why can't "what" be the subject?

This isn't exactly a backwards construction, since the only trouble is inside a modifier, not in the sentence core. As for "What are," this is the normal usage of "what." It takes its singular/plural cues from what follows.* Thus, we say "What is linear algebra?" or "What are qubits?" In this sentence, "what are" basically means "things that are." If it said "what is," it would mean "a thing that is."

Two examples:
I don't want to spend time debating the merits of what is clearly a doomed piece of legislature.
Many doctors at the time were highly dismissive of what are now considered the cornerstones of palliative care.



*Funny coincidence--just now I said "what follows" and nothing followed, so the default is singular.
_________________