Sentence Correction

Scientists are currently trying to determine the extent to which tectonic plates have been shifted from their previous positions by earthquakes and other similar phenomena.

A. to which tectonic plates have been shifted
B. to which tectonic plates have shifted
C. of the shift of tectonic plates
D. of tectonic plate shifting
E. that tectonic plates have been shifted

Answer A

Kaplan explanation for C:
You can eliminate C because of the shift...to earthquakes is incomplete without a verb.
What does that mean?

Also, is extent of wrong?

Thanks!

there are different ways in which u can see this problem .the fact that the non underlined portion of this sentence has the construction "by earthquakes and other similar phenomena" so we need a passive voice construction .that passive voice verb is missing if C were the answer !!
in fact it is precisely for this reason that A is the answer and not B
also "extent of" per se is not wrong

Hi,

Options C,D,E are not idiomatically consistent in the context of the sentence. Since author is trying to emphasize on the "degree" or "level" of shift from their previous positions, the idiom "EXTENT TO" is appropriate rather than "EXTENT OF" or "EXTENT THAT". Now, between choice A and B present perfect continuous is needed, though I feel it should have been "SHIFTING" instead of "SHIFTED".

sparkles3144 wrote:Scientists are currently trying to determine the extent to which tectonic plates have been shifted from their previous positions by earthquakes and other similar phenomena.

A. to which tectonic plates have been shifted
B. to which tectonic plates have shifted
C. of the shift of tectonic plates
D. of tectonic plate shifting
E. that tectonic plates have been shifted

Answer A

Kaplan explanation for C:
You can eliminate C because of the shift...to earthquakes is incomplete without a verb.
What does that mean?

Also, is extent of wrong?

Thanks!

Non underlined portion of the sentence says - by earthquakes and other similar phenomena, which means a passive construction is required. Based upon this, we eliminate B, C and D.

Extent to is correct usage in this context.so, E eliminated

A is the best answer