Sentence Correction

The Neanderthals, once considered dull-witted brutes, are now known to have had brains fully as large as our own.

(A) to have had brains
(B) as having brains that are
(C) to have brains that were
(D) that their brains were
(E) that they had brains that were


Although OA: A, I want to know why C & D are wrong? Both give same tense in the past.

Thanks

Mo2men wrote:The Neanderthals, once considered dull-witted brutes, are now known to have had brains fully as large as our own.

(A) to have had brains
(B) as having brains that are
(C) to have brains that were
(D) that their brains were
(E) that they had brains that were


Although OA: A, I want to know why C & D are wrong? Both give same tense in the past.

Thanks

The perfect infinitive can be used to refer to something in the past.

Dinosaurs are known to walk the Earth.
Present infinitive. Implies that dinosaurs still walk the Earth.

Dinosaurs are known to have walked the Earth.
Perfect infinitive. Used here to indicate that Dinosaurs no longer walk the Earth.

Note that we can't simply change the are to were to communicate that dinosaurs no longer walk the Earth, as doing so could be interpreted as implying that the knowing is not current, that is, we no longer know that dinosaurs walk the Earth. Alternatively, the sentence could be talking about the state of knowing at some time in the past (for example, to point out when that fact was first known).

Option D should use it as the subject to delay the that clause instead of providing a completely different subject.

It is known that dinosaurs walked the Earth.
This sentence is fine.

Dinosaurs are known that they walked the Earth.
This one is not.

In English, we have two infinitive tenses: the present infinitive (to + VERB) and the perfect infinitive (to have + VERBed).

The present infinitive expresses CONTEMPORANEOUS action (an action happening AT THE SAME TIME as the main action):
John IS proud TO BE president.
Here, John IS proud (in the present) TO BE president (also in the present).

The perfect infinitive expresses PRIOR action (an action that happened BEFORE the main action):
John IS proud TO HAVE BEEN president.
Here, John IS proud (in the present) TO HAVE BEEN president (in the past).

Mo2men wrote:The Neanderthals, once considered dull-witted brutes, are now known to have had brains fully as large as our own.

(A) to have had brains
(B) as having brains that are
(C) to have brains that were
(D) that their brains were
(E) that they had brains that were

OA: The Neanderthals, once considered dull-witted brutes, are now known to have had brains fully as large as our own.
Here, the Neanderthals ARE NOW KNOWN (in the present) TO HAVE HAD brains (in the past).
This sequence is logical.

C: are now known to have brains
Here, the Neanderthals ARE NOW KNOWN (in the present) TO HAVE brains (also in the present).
Since the Neanderthals no longer exist, this meaning is nonsensical.
Eliminate C.

A VERBing modifier serves to express an action that is CONCURRENT with the main action.
B: are now known as having brains
Here, the usage of having implies that the Neanderthals are HAVING brains NOW.
Since the Neanderthals no longer exist, this meaning is nonsensical.]
Eliminate B.

Mary knows that the house is blue.
Here, the that-clause in blue serves as the DIRECT OBJECT of knows.
WHAT does Mary know?
She knows THAT THE HOUSE IS BLUE.
Rule:
A passive verb -- is + VERBed, are + VERBed, etc. -- cannot take a direct object.

D: are now known that their brains were
E: are now known that they had brains
Here, each of the that-clauses in red seems to be serving as the direct object of are known (passive verb).
Since a passive verb cannot take a direct object, eliminate D and E.

The correct answer is A.

GMATGuruNY wrote:
D: are now known that their brains were
E: are now known that they had brains
Here, each of the that-clauses in red seems to be serving as the direct object of are known (passive verb).
Since a passive verb cannot take a direct object, eliminate D and E.

The correct answer is A.

Thanks Mitch for your help.

1- Is there any difference between 'known as' and 'known to'? which one is idiomatic and when to use?

2- is the structure 'It is known that.....'correct? I believe so because it is 'empty it' structure. Am i right?

Mo2men wrote: Thanks Mitch for your help.

1- Is there any difference between 'known as' and 'known to'? which one is idiomatic and when to use?

X is known as Y.
Here, Y = a name or classification for X.
SC67 in the OG13:
the animal known as the killer whale
Here, the phrase is blue = a name for the animal.

B: The Neanderthals are known as having brains
Here, the phrase in red does not constitute a NAME for the Neanderthals.
Thus, the usage of known as is inappropriate.
Eliminate B.

X is known to Y.
Here, Y = an action or state-of-being attributed to X.
OA: The Neanderthals are known to have had brains fully as large as our own.
Here, the phrase in blue = an action attributed to the Neanderthals.

Here
2- is the structure 'It is known that.....'correct? I believe so because it is 'empty it' structure. Am i right?

It is known that X is greater than Y.
Here, it is standing in for the that-clause in blue.
Conveyed meaning:
THAT X IS GREATER THAN Y is known.
In this structure, the that-clause serves as the SUBJECT of is known.
This structure is grammatically correct.

ceilidh.erickson wrote:Here is another OG question that tests the know as / know to distinction. This is SC #71 in OG 11:

The cameras of the Voyager II spacecraft detected six small, previously unseen moons circling Uranus, which doubles to 12 the number of satellites now known as orbiting the distant planet.

(A) which doubles to 12 the number of satellites now known as orbiting
(B) doubling to 12 the number of satellites now known to orbit
(C) which doubles to 12 the number of satellites now known in orbit around
(D) doubling to 12 the number of satellites now known as orbiting
(E) which doubles to 12 the number of satellites now known that orbit

OA B

Thanks for your support but i have quick question?

what is the meaning of 'doubling to 12 the number'? what is the mathematical interpretation?