How can we know that the ‑ing forms are not used as a verb but as a noun?
The only way you can tell whether an ‑ing word is actually a noun or a verb is to see whether you can:
Do "noun things" to it, like:
(A) modify it with an adjective "a big X-ing", or
(B) use it in noun-only constructions such as "the X-ing of Y" where you connect two noun phrases with a preposition.
Do "verb things" to it, like:
(C) modify it with a manner adverb like "Y-ly X-ing", or
(D) use it with an object complement like "X-ing the Y".
However, this doesn't matter at all. Believe it or not, you do not need to know this.
All you need to learn is what things the verb allow can accept following
it, not whether each possible use of this or that random ‑ing word
following it is a noun or a verb or an adjective. That never matters at
To that end, the allowable predicate frames for allow are shown here in
its Lexico entry. And for your
purposes, what allow accepts really boils down to either one or two
object complements, both of which are always noun phrases.
When there are two object complements, the first noun phrase
represents the person being allowed to do something and the second noun
phrase is an infinitive clause saying what that person is being allowed to
do. (This works almost like the verb works in let someone do
something, except that with allow the to particle must be explicit in
allow someone to do something.)
When there is only one object complement, this is a noun phrase
naming just what it is that's being allowed, as in allow horses or allow
horse racing or allow racing horses. This single noun phrase cannot be an infinitive clause, but it can be a
gerund-participial clause with an ‑ing verb heading it, as in allow
doing something like allow smoking a cigarette or two during your lunch
All these examples following are grammatical. The first three examples and example (9) all
take two object complements, while the rest all take just one object
complement. Sometimes these complements are nonfinite clauses headed by a
verb; other times they're noun phrases that are headed by a noun or are
just a personal pronoun by itself in object case such as you or me or
him or her.
- We cannot let you race your turtles here. (race is a verb here)
- You are not allowed to race your turtles here. (race is a verb here)
- We cannot allow you to race your turtles here. (race is a verb here)
- We cannot allow racing turtles slowly here. (racing is a verb here)
- We cannot allow racing slow turtles here. (racing is a verb here)
- We cannot allow the racing of slow turtles here. (racing is a noun here)
- We cannot allow slow racing turtles here. (racing is a noun here)
- We cannot allow slow turtles racing here. (racing is a verb here)
- We cannot allow slow turtles to race here. (race is a verb here)
- We cannot allow slowly racing slow turtles down our racetrack. (racing is a verb here)
- We cannot allow turtle racing here. (racing is a noun here)
- We cannot allow more time for turtle racing. (racing is a noun here)
- We cannot allow more time for turtles racing so slowly. (racing is a verb here)
- We cannot allow more time for racing slow turtles. (racing is a verb here)
- We cannot allow your slow racing turtles any more time to finish the race. (racing is a noun here)
- We cannot allow your turtles any more time to finish slowly racing down our course. (racing is a verb here)
As you see, I've gone to the trouble of adding a few extra words around any
‑ing words to help make it clear whether the complementary noun phrase's
head is a noun or a verb. I did this only because you asked, not because it
matters at all. That's because, just as I said starting out, whether an ‑ing word
happens to be a noun or a verb doesn't make any difference when it comes to
knowing which sorts of predicate frames are grammatical with allow.