Researchers hypothesize that granitic soil is the ideal construction

One slight adjustment here. The verb form we want after could, might, etc. is not the plural but the bare infinitive. (That's the infinitive--"to" form--minus the "to.") You can see this clearly with irregular verbs: we say "could be" and not "could are."
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Hello guys! In this question I was hesitant to select A because of the presence of "could" It is generally used in conditional situation or hypothetical. the tense changed in the second half of the sentence with could. Can you please justify the use of could here?? IanStewart AndrewN

Hello, pk6969. Note that in the sentence in question, the first half of the explanation/comparison focuses on the tortoise, on something the animal actually does, while the second focuses on a hypothetical situation that does not actually occur (because the soil is not too soft).


The usage of could is wholly appropriate, the action of the tortoise suggested at the end: so soft that it could cause tunnels to collapse [while the tortoise was burrowing]. Sure, the sentence could be written differently—i.e. so soft that it causes tunnels to collapse [while the tortoise burrows/is burrowing]—but that is not an option, so we are forced to reconsider whether parallel elements must be one-to-one matches, and the OA tells us which way to lean. In terms of logical predication, I prefer the could version: I understand that I am being provided a glimpse into a scene that does not occur but could occur under different circumstances.

I hope that helps. Thank you for thinking to ask.

- Andrew
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Is the usage of 'nor' correct in option E?

Researchers hypothesize that granitic soil is the ideal construction material for the desert tortoise because it is not so hard that it makes burrowing difficult or so soft that it could cause tunnels to collapse.

Option Elimination -

(A) so hard that it makes burrowing difficult or so soft that it could cause - use the correct cause and effect. So "hard" (cause) that "it makes burrowing difficult" (effect). "it" refers to soil.

(B) hard enough to make burrowing difficult or soft enough as to cause - "enough to" is used to show adequacy. E.g., Sarah studied hard enough to earn a scholarship. But it is not used for cause and effect. Moreover, "enough as to" after "or" is wrong.

(C) so hard as to make burrowing difficult or soft enough so it causes - the usage of " so (cause) as to (effect) is not parallel.

(D) as hard as to make burrowing difficult or as soft as to cause - there is no comparison here. "as X as" is used for comparison. E.g., She is as tall as her sister. There is no comparison here.

(E) too hard, making burrowing difficult, nor too soft, so as to cause - "so as to" means "in order to" E.g., She arrived early so as to secure a good seat for the presentation. The construction ("nor too soft" in order to cause to tunnels to collapse) is a total mess.

Hi DmitryFarber and other experts,

Am i right here to think that we dont need anything in past mood or tense before the clause after 'THAT' to make it hypothetical, as we need in Would' construction ?

Kindly help ?

Thanks !

SnorLax_7

That's right. The first clause after that ("it makes burrowing difficult") isn't hypothetical at all, and the second one makes a simple hypothetical with "could." We can always say that something COULD happen without the need for a special setup. "I could eat these chips all day."
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