idiom and logical predication

[wsypinero]

Intuits of Bering Sea were in isolation from contact with Europeans longer than Aleuts or Intuits of the North Pacific and northern alaska.

a. in isolation from contact with europeans longer than
b. isolated from contact with europeans longer than
c. in isolation from contact with europeans longer than were
d. isolated from contact with europeans longer than were
e. in isolation and without contacts with europeans longer than

i selected b but the answer was d

i'm having a hard time understanding why "were" is needed after than. additionally, can someone provide me a reason why "in isolation from" is incorrect. currently it just sounds awkward but i would prefer to have a specific reason why it is incorrect.

OG Supplement SC Question 106

[srikanth.vid]

'were' is required as it would be parallel to "Intuits of Bering Sea were".

I thought C was the answer initially, but I am not sure why "in isolation from" is incorrect. Can some one please through light on this issue.

[wsypinero]

I agree with your explanation. However, why is "were" after "than" an not after "alaska?"

Intuits of Bering Sea were in isolation from contact with Europeans longer than Aleuts or Intuits of the North Pacific and northern alaska.

[ayushrastogi82]

i'm having a hard time understanding why "were" is needed after than.

We cannot omit 'were' here because without 'were' the sentence would become ambiguous as mentioned below:

Intuits of Bering Sea were isolated from contact with Europeans longer than [were] Aleuts or Intuits of the North Pacific and northern alaska.

OR

Intuits of Bering Sea were isolated from contact with Europeans longer than [from] Aleuts or Intuits of the North Pacific and northern alaska.
[editor: i changed this to the correct form.]

[editor: well done.
this problem is easier to consider if you replace long strings, such as "aleuts and inuits of ...", with a single letter.

i.e., it's probably easier to understand the difference if you compare
X were isolated from E longer than from Y
with
X were isolated from E longer than were Y

[RonPurewal]

'were' is required as it would be parallel to "Intuits of Bering Sea were".

I thought C was the answer initially, but I am not sure why "in isolation from" is incorrect. Can some one please through light on this issue.

it's unidiomatic.

you can't say "in isolation from X"; it's just "in isolation".
ironically, you have to use "in isolation" in isolation. heh.

even if you don't know this, though, you should still pick "isolated" on the grounds that it's more concise.