Consider the following examples:
- I paid for it by using my credit card.
- I was in contact with my friends by sending letters.
- I learned how to dance by watching online videos
if I remove the preposition "by", one of them sound fine (the first one), but the others sound different:
- I paid for it using my credit card.
- I was in contact with my friends sending letters. (sounds like my friends are sending letters)
- I learned how to dance watching online videos. (sounds like I learned while watching videos in the background)
so I have two questions:
- What is the difference between these sentences that makes them behave differently under "by" preposition
- What is the resulting phrase (I paid for it using my credit card) and its grammatical function?
"by using my credit card" is obviously an adverbial (a prepositional phrase), and "using my credit card" is a gerund phrase. This is confirmed if we use a pronoun instead: I paid for it by this. But what is the role of "using my credit card" after removing "by"? It can no longer be considered as a gerund phrase because it’s not functioning as a noun and cannot be replaced with a noun (I paid for it cash).
But what would be its function if it is a participle phrase? it doesn’t seem to modify the subject "I" (it’s not like I paid for it while I was using and playing with my credit card). I can’t put it in an adverbial sense either, even though it looks like an adjunct.
I paid for it by using my credit card. – "by using my credit card" is a prepositional phrase consisting of a preposition + a gerund phrase. It is a bound modifier and modifies "paid"
I paid for it using my credit card. – "using my credit card" is a participle phrase used as a free modifier, i.e. it modifies the main clause "I paid for it" adverbially.
This latter point is probably clearer as Using my credit card, I paid for it, which is to be understood as "I was using my credit card when I paid for it."