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.