jainrahul1985 wrote:Five hundred million different species of living creatures have appeared on Earth, nearly
99 percent of them vanishing.
A. Five hundred million different species of living creatures have appeared on Earth,
nearly 99 percent of them vanishing. - bad constructionB. Nearly 99 percent of five hundred million different species of living creatures that
appeared on Earth have vanished. - incomplete! (PAST)
C. Vanished are nearly 99 percent of the five hundred million different species of
living creatures that appeared on Earth. - Ambiguous
D. Of five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent of them have vanished.
E. Of the five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent have vanished

OA E . why are B and D wrong ? . Also help me understand correct usage of past and past perfect usage here .

IMO:E

E conveys the meaning more clearly but I don't get what is wrong in B ? Can someone explain ?

jainrahul1985 wrote:Five hundred million different species of living creatures have appeared on Earth, nearly
99 percent of them vanishing.
A. Five hundred million different species of living creatures have appeared on Earth,
nearly 99 percent of them vanishing.
B. Nearly 99 percent of five hundred million different species of living creatures that
appeared on Earth have vanished.
C. Vanished are nearly 99 percent of the five hundred million different species of
living creatures that appeared on Earth.
D. Of five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent of them have vanished.
E. Of the five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent have vanished

OA E . why are B and D wrong ? . Also help me understand correct usage of past and past perfect usage here .

Keep it simple: all the verbs should be in the same tense unless there is a compelling reason to change tenses. In B and C, there is no compelling reason for APPEARED to be in the past tense while HAVE VANISHED (in B) and ARE (in C) are in forms of the present tense. Eliminate B and C.

In D, OF them is redundant with OF five hundred million species.

A present participle (VERBing) implies CONTEMPORANEOUS action: one action happening at the same time as another action. Thus, the present participle in A implies a nonsensical meaning: that the species [have been] VANISHING at the same time as they HAVE APPEARED. Eliminate A.

The correct answer is E.

Regarding the mix of tenses in B and C:
If the species only APPEARED in the past, the implication is that they also DISAPPEARED in the past. Thus, B and C would need to put all of the verbs in the past tense: the species APPEARED, but then they VANISHED. Putting both actions in the past, however, would change the intended meaning of the sentence.

jainrahul1985 wrote:Five hundred million different species of living creatures have appeared on Earth, nearly
99 percent of them vanishing.
A. Five hundred million different species of living creatures have appeared on Earth,
nearly 99 percent of them vanishing.
B. Nearly 99 percent of five hundred million different species of living creatures that
appeared on Earth have vanished.
C. Vanished are nearly 99 percent of the five hundred million different species of
living creatures that appeared on Earth.
D. Of five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent of them have vanished.
E. Of the five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent have vanished

OA E . why are B and D wrong ? . Also help me understand correct usage of past and past perfect usage here .

B is wrong because it changes the intended meaning of the sentence by introducing that appeared