sc question - tenses

[mkhanna]

Q) Scientists are currently trying to determine the extent [u]to which tectonic plates have been shifted[/u] 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 places
(D) of tectonic plate shifting
(E) that tectonic plates have been shifted

[vishal1702]

Extent that is unidiomatic in E

tectonic plate doesn't agree with their in the non-underlined part in D

In C, .....the extent of the shift of.... makes it awkward

Btw A & B i would go with A because it sounds better when you say ...have been shifted...by earthquakes(kind of passive voice) rather than saying ....have shifted....by earthquakes. I know its not the most clear reasoning one can give, but that is how i feel...

OA plz...

[arorag]

Will go B
G

[riteshbindal]

B IMO too.

[lihtnes78]

Between A and B, I am really not sure.

if there was a option like
"to which tetronic plates has shifted", that would have made it even
more confusing.

Please post the official answer.

[sk8ternite]

Q) 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 places
(D) of tectonic plate shifting
(E) that tectonic plates have been shifted

I think its B, have been shifted, the present perfect progressive, states that the action has continued and is not completed. The shifting from their previous positions by earthquakes and other similar phenomena started in the past and has finished so we need present perfect.

[riteshbindal]

What's the OA mkhanna?

[capnx]

I think it's A.

..determine the extent to which tectonic plates have been shifted...by earthquakes and other similar phenomena.

so passive form is needed.

[mkhanna]

the correct answer is A.

I found this question in OG verbal. The explanation said that "have been shifted" sounds better than "have shifted", but I really don't understand why...

"Have shifted" makes the sentence more concise, doesn't it?

[enniguy]

The difference between A & B is that B is passive.
1. Here passive voice is necessary because subject comes at last. Who/What shifted the tectonic plates? Earthquake.
2. Apart from that, the sentence after the underlined part describes the action. Hence passive voice must be there.
3. Note the presence of "by" in non-underlined sentence.
Active:Alice threw the ball.
Passive: The ball was thrown by Alice.
4. ( I am not sure about this point ) shifted is past participle. So you can expect the subject to come in the end. Hence, passive.

Also, "from their previous positions" modifies shifted. Hence it has come in the middle of a much simpler passive sentence:
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.

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The reason why A is correct and B is not is that "have shifted" implies that tectonic plates shifted automatically (or by themsleves), which is wrong.. "Have been shifted" is the right word because it implied that Earthquakes have caused tectonic plates to shift..

[mkhanna]

Hmm..that's logical. Thanks so much. very helpful!

[anand0408]

Also, "have shifted" won't be followed by "by"....it will be followed by "due to" or "because"

[oagostinho]

The reason why A is correct and B is not is that "have shifted" implies that tectonic plates shifted automatically (or by themsleves), which is wrong.. "Have been shifted" is the right word because it implied that Earthquakes have caused tectonic plates to shift..

Hi,

I read that: have +been+ past participle => passive voice!
In that way, like you said , B is not correct!

Thanks!