- to turn it on is forbidden
- turning it on is forbidden
I always have troubles when I have to use infinite forms of verbs. In particular like in this example, where a verb describes something more in the next sentence.
I mean when a verb is the subject of a sentence, i.e.: "Walking is healthy" vs "To walk is healthy". I seem to hear more the first version, but some times I wonder if the -ing form is always the correct way.