Sentence Correction

Q1. Cooperative appartment houses have the peculiar distinction of being dwellings that must also operate as businesses.

A. Of being dwellings that must also operate as businesses.
B. Of dwellings that must also operate like businesses.
C. that they are dwelling that must operate like as businesses.
D. that, as dwellings, they must also operate like businesses.
E. to be a dwelling that must operate as a business.

Doubt: "That" is genrally used for singulars but here in the answer it is used for "dwellings". Why so?

Q2. During the Renaissance, scholars were uncertain as to the location of Troy, and by the eighteenth century many historians doubted that Troy had ever existed.

A. Same as in sentence
B. doubt that troy has ever existed
C. were in doubt as to the existence of troy
D. were doubtful concerning troy's existence
E. had doubts about troy's ever existing

Doubt: Why C is incorrect?

Q3. It may be another fifteen years before spacecraft from Earth again venture to Mars, a planet now known to be cold, dry, and probably lifeless.

A. Same as in sentence
B. venture to Mars again, a planet now known for being
C. will venture to Mars again, a planet now known as being
D. venture again to Mars, a planet that is known now to be
E. will again venture to Mars, a planet known now as being

Doubt: Why E is incorrect.

Answers: Q1 A Q2 A Q3 A

what's the source ?

1. Cooperative appartment houses have the peculiar distinction of being dwellings that must also operate as businesses.

A. Of being dwellings that must also operate as businesses. \

OUT: as should start a clause.
B. Of dwellings that must also operate like businesses.

Correct: distinction of x... ( correct idiom)

C. that they are dwelling that must operate like as businesses.
wrong idiom
D. that, as dwellings, they must also operate like businesses.
wrong idiom
E. to be a dwelling that must operate as a business.
wrong idiom




During the Renaissance, scholars were uncertain as to the location of Troy, and by the eighteenth century many historians doubted that Troy had ever existed.

A. Same as in sentence

Correct: Active.. past perfect right used...
B. doubt that troy has ever existed
past perfect required....

C. were in doubt as to the existence of troy
passive
as to the existencce... awkward
D. were doubtful concerning troy's existence

passive
E. had doubts about troy's ever existing
awkward

thanks ronnie, the source is material from some coaching institute for gmat

A. Same as in sentence

Correct: Active.. past perfect right used...



Why is Past Perfect Verb required here ?? Could you please explain ?

Why not C..??
It maintains the parallelism...!!

For 1) B is not correct due to: like which is used to compare noun and noun phrase but here businesses is compared iwth clause

see the below link
https://www.urch.com/forums/gmat-sentenc ... 226-a.html

My only doubt in que no 2 is why is A correct
Why do we ignore the obivious error in A

again venture to Mars, a planet now known to be

lets look at it other way:
It may be long before something happens(not happen)

Isnt this wrong?

I disagree with OA here