(A) The online game is so popular that the company will soon start a new version and will [add new feathers allowing players to] buy real gifts for their partners. (B) The online game is so popular that the company will soon start a new version and will [add new feathers to allow players to] buy real gifts for their partners. (C) The online game is so popular that the company will soon start a new version and will [add new feathers to allowing players to] buy real gifts for their partners.
Top answer
The first two are fine. The last one is wrong. You want either the infinitive "to allow" or the participle "allowing".
— CalifJim
The first two are fine.
The last one is wrong.
You want either the infinitive "to allow" or the participle "allowing".
Combining both into one (where "to" is not a preposition), as in "to allowing", is never seen in English.
Note that if "to" is used as a preposition, the combination can occur, as in the expression "adverse to".
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The first two are fine. The last one is wrong. You want either the infinitive "to allow" or the participle "allowing". Combining both into one (where "to" is not a preposition), as in "to allowing", is never seen in English.
Note that if "to" is used as a preposition, the combination can occur, as in the expression "adverse to".