OG12_SC004_Explained!

Of all the vast tides of migration that have swept through history, maybe none is more concentrated as the wave that brought 12 million immigrants onto American shores in little more than three decades.

(A) maybe none is more concentrated as
(B) it may be that none is more concentrated as
(C) perhaps it is none that is more concentrated than
(D) maybe it is none that was more concentrated than
(E) perhaps none was more concentrated than

Explanation:

Concept one:

X is more ......................than Y, 

Where X and Y MUST be grammatically parallel.

When we see "More" , we must search for "Than" because "More than" is correct.

The followings are WRONG:

X is more .........................AS Y

Elimination: The options A and B have used "More ........as", which is wrong. They are eliminated.

Concept Two:

It is none that is/was can be replaced by shorter alternative "none is/was"; GMAT prefers shorter sentences. 

In the options C and D, "it is none that is/was" is redundant. We can eliminate C and D.

Answer: E

OG12_SC003_Explained

Although various eighteenth- and nineteenth-century American poets had professed an interest in Native American poetry and had pretended to imitate Native American forms in their own works, until almost
1900, scholars and critics did not begin seriously to study traditional Native American poetry in native
languages.

(A) until almost 1900, scholars and critics did not begin seriously to study
(B) until almost 1900 scholars and critics had not begun seriously studying
(C) not until almost 1900 were scholars and critics to begin seriously to study
(D) it was not almost until 1900 when scholars and critics began to seriously study
(E) it was not until almost 1900 that scholars and critics seriously began studying

Explanation:
Concept one:
Clause, Adverb, Clause makes the problem.
Example:
Though she had scored higher, in 1990, the score is no more valid. 
Now, we have a confusion about the position of "in 1990". It has two meanings:
1. She had scored higher in 1990.
2. The core is not valid in 1990.

Conclusion: The structure "Clause, Adverbial phrase, clause" creates an ambiguous sentence.

Elimination: This rule eliminates the option A.

 Concept Two:

 We cannot use two past perfect tense in the same sentence.
We can use: 

Perfect+ Simple Past => They had reached the station before the train left.
Simple Past + Past perfect=> They came after the train had left.

Elimination: This rule eliminates the option B.

Concept Three:

Memorize the following rule. [Take note.]

To Begin + To Study  is WRONG

 I have searched google by "to being to study", and I have found the following search results:

To begin study

To begin a study

To begin studying

To begin your study

To begin the study

Began to study

--> All these sentences are CORRECT.

This implies that the form "To BEGIN to STUDY" is WRONG.

Elimination: This rule eliminates C

Concept Four:

Almost until 1990 is not idiomatic.

--> Almost should modify 1990, but in the present form it is in a remote place to modify 1990. 

--> Almost 1990 means around 1990. Almost until 1990 creates a vague modification. 

--> Until almost 1990 is okay in this sense.

Elimination: This rule eliminates D. 

Answer: E. 

Official Guide_10_SC01

The Wallerstein study indicates that even after a decade young men and women still experience some of the effects of a divorce occurring when a child.

(A)  occurring when a child

(B)  occurring when children

(C)  that occurred when a child

(D)  that occurred when they were children

(E)  that has occurred as each was a child

Key Points to Know:

1. A divorce occurring when a child.

This illogically means that “a divorce was a child”. This rule eliminates A and B.
2.  "Men and Women" is Plural; therefore, the use of "a child" is wrong. This rule eliminates C and E. 


Answer is D.

OG12_SC002_Explained.

OG12_SC002:

Although a surge in retail sales have raised hopes that there is a recovery finally under way, many  economists

say that without a large amount of spending the recovery might not last.

(A)   have raised hopes that there is a recovery finally

(B)    raised hopes for there being a recovery finally

(C)    had raised hopes for a recovery finally being

(D)    has raised hopes that a recovery is finally

(E)    raised hopes for a recovery finally

Explanation from Nazar:

Skeleton of the sentence:

A surge have raised hopes that there is a recovery finally underway.

The problems in the original sentence:

1. The subject of the sentence is "A surge", which is singular, and the verb "have" is in PLURAL. 

2. There is/ there are type structures are always seen as awkward and redundant in GMAT.

Eliminate A.

Other issues in the wrong options:

BEING:

Being is not always WRONG though it is wrong 95% of the time. We must know when the use of BEING is is wrong and when the use of BEING is correct.

BEING is CORRECT:

1. If it used as auxiliary verb in PASSIVE sentence of progressive TENSES.

Example:

Active: They were playing football.

Passive: Football was being played by them.

Active: We are writing explanations.

Passive: Explanations are being written by us.

2. If it is use as GERUND.

Example:

Being heavily committed to the work brings success. 

When the use of BEING is WRONG:

If the use of BEING is with Case in Apposition:

Example:

Mr. John, being the head of the department, has made the decision.

Revised: Mr. John, the head of the department, has made the decision.

--> See the revised option is good, and the use of being in the first option does not add anything in the sentence. 

If we see any BEING used with appositive, we can ignore the BEING. 

Now, see the BEING in the options

Past simple:

We use past simple tense in those sentence where there will have past marker such as yesterday, last night, last year, last decade, year in the past. We don't have any such past marker in the sentence.

Eliminate the option E.

Answer is D.

OG12_SC001_Explained.

OG12_SC1: 

The Glass House Mountains in Queensland, Australia, were sighted in 1770 by the English navigator Captain  James Cook, by whom they were named supposedly because its sheer wet rocks glistened like glass.

(A)          by whom they were named supposedly because its

(B)          by whom they were named supposedly and their

(C)          naming them supposedly since their

(D)          who so named them supposedly because their

(E)          who so named it since supposedly their

Explanation from Nazar:

The skeleton of the sentence:

The Glass House Mountains were sighted by James Cook, by whom they were named supposedly because its sheer wet rocks glistened glass.

Find the errors of the original Sentence:

1. Its and it in the options A and E do not agree with the plural antecedent MOUNTAINS.  Eliminate A and E.

2. By whom is not correct because COMMA + By whom  does not have action. 

--> Eliminate the options  A and B.

Example:

The work has been done by John, who is efficient.--Correct.

Active: Who has done the work?

Passive: By whom has the work been done?

--> The work has been done by whom?

3. COMMA + VERB-ING:

Usually COMMA+VERB-ING modifies the entire preceding clause and retains the subject of the preceding clause. Two things must be borne in mind:

I. There must be a "SUBJECT+VERB" before COMMA + VERB-ING.

II. The subject of the clause before COMMA+VERB-ING is the subject of the VERB in the VERB-ING.

Now, test the option C.

Subject of the preceding clause is "MOUNTAINS". 

We can fix: MOUNTAINS name.

Can mountains do the task of naming? Nope.

Eliminate the option C.

Answer is thus D.