Why is the -ing form of the verb used after prepositions? And is it the case with EVERY preposition or are there exceptions?
Functions of the -ing form
When we learn English, we learn early on that verbs have a so called -ing form. This usually happens when we learn about the progressive (or continuous) tenses, for example:
I am writing a letter. (present continuous)
He was sitting on my chair. (past continuous)
We‘ve been living here for three years. (present perfect continuous)
Indeed, this is one of the TWO KINDS of -ing form:
1. The present participle
This -ing form, which follows the verb ‘be’ in continuous tenses, is called the present participle. It can function:
- as a verb form in continuous tenses: I‘m playing chess this afternoon.
- or as an adjective: exciting, boring, interesting (This is a very exciting book.)
2. The gerund
However, there is this other -ing form, which we use after prepositions!
That is called gerund. Yes, the name comes from Latin grammar, where there was a similar verb form. Now, the gerund is formed from verb stems (adding the –ing), but has functions in the sentence like nouns do. It’s neither a true verb, nor a true noun, but has qualities of both.
The gerund truly acts just like a noun in the sentence, so it can be:
- subject: Running is not my favourite activity.
- object: I hate running. (Sorry, runners!)
- subject complement: One sport that everyone likes is cycling.
- and object of a preposition: I read a lot about fishing. // He doesn’t approve of smoking. // What are the chances of winning the lottery?
And since prepositions can ONLY BE FOLLOWED BY NOUNS (and some clauses), we have to use the gerund form of the verbs when we want to put them after any preposition. Always!