Sentence Completion reg the use of infinitives and gerunds.

[sparsha.n]

Hi,

This is Q109 from The OG for GMAT Review. I was able to narrow it down to two choices but could not understand when to use the infinitive "to heal" and when to use the gerund "Healing".

[deleted because problem is from a banned source - see below]

The above sentence is correct but one of the options has "to heal" instead of "healing". I understand the word aid is used as a noun here but I am still confused about when I should use the gerund and when I should use an infinitive. Thanks.

[pellucide]

I am also waiting for an answer. Just for reference, The complete question is here.

[deleted because problem is from a banned source - see below]

[elevinty]

Here's my understanding.
this is idiom issue.
if AID is a noun in a sentence, "IN" must follow AID.
if AID is a verb in a sentence, "INFINITIVE TO" follows AID.

[tim]

OG is a banned source; it is illegal to post OG questions anywhere on the web. If you are in one of our classes, please ask OG questions during office hours or before/after class..

As for this particular question, it's an idiom. Just memorize them and move on. Sorry we can't be of more help on these, but that's the way idioms are..