Sentence Correction

Nobody knows exactly how many languages there are in the world, partly because of the difficulty (of? ) distinguishing between a language and the sub-languages or dialects within it, but those who have tried to count typically have found about five thousand.
A) and the sub-languages or dialects within it, but those who have tried to count typically have found
B) and the sub-languages or dialects within them, with those who have tried counting typically finding
C) and the sub-languages or dialects within it, but those who have tried counting it typically find
D) or the sub-languages or dialects within them, but those who tried to count them typically found
OA is A Why not D. A option uses IT though I think them should be used as languages are prular.
Please explain.

hey hmboy17,
The key to answering this question is knowing what it is testing.

First, there's a framework #5 idiomatic expression: "between A and B"
Notice you cannot say "between A or B"---therefore, scanning through the answer choices, D is wrong. This leaves you with A, B, and C.

Next, look at A. Is there anything wrong? Well, you point it that "it" refers to "languages"---this is incorrect!. Look at the phrasing.

"Distinguishing between a language and the sub-languages or dialects within it"

"it" refers to "language"---not "languages" mentioned earlier in the sentence!

So that gets rid of B. Between A and C, the only difference is the verb tenses:
A: "those who have tried to count typically have found"
vs
C: "those who have tried counting it typically find"

What's wrong? Well, there's 2 things wrong with (C):
1) "it" refers to "language" from a structural standpoint even though we know from a meaning perspective, it refers to "languages"
2) the verb tense is not consistent. "have tried" should be followed by "have found"

Choice (A) does not have these problems. Therefore, (A) is the answer.

gmatpill wrote:hey hmboy17,
The key to answering this question is knowing what it is testing.

First, there's a framework #5 idiomatic expression: "between A and B"
Notice you cannot say "between A or B"---therefore, scanning through the answer choices, D is wrong. This leaves you with A, B, and C.

Next, look at A. Is there anything wrong? Well, you point it that "it" refers to "languages"---this is incorrect!. Look at the phrasing.

"Distinguishing between a language and the sub-languages or dialects within it"

"it" refers to "language"---not "languages" mentioned earlier in the sentence!

So that gets rid of B. Between A and C, the only difference is the verb tenses:
A: "those who have tried to count typically have found"
vs
C: "those who have tried counting it typically find"

What's wrong? Well, there's 2 things wrong with (C):
1) "it" refers to "language" from a structural standpoint even though we know from a meaning perspective, it refers to "languages"
2) the verb tense is not consistent. "have tried" should be followed by "have found"

Choice (A) does not have these problems. Therefore, (A) is the answer.

Can some one please explain why "have tried" must follow by "Have found". Present perfect can pair with present tense?

Why "have tried" must be followed by "Have found"? Present perfect can't pair with simple present tense?