I'm not a native English speaker, and although I know the general rules to identify whether it is a gerund or participle, sometimes I'm still confused about how to distinguish the gerund and present participle, particularly in the example as below. This is a sentence which I saw in the usage of phrase "depend on" from the Longman Dictionary. My question is that whether the "-ing" form in this sentence is a gerund, in which case it functions as a noun, or this is a present participle which refers to the pronoun i.e. "him" and modifies this pronoun.
depend on somebody/something doing something
We’re depending on him finishing the job by Friday.
(Longman Dictionary of Contemporary English Online)
Best Answer
Although modern grammar doesn't recognize the difference between gerunds and present participles, if we were to distinguish them, then in your case we would have a 'gerund'. The clearest way to see this is to note that you can replace the accusative him by the genitive his, and the genitive can only work with the 'gerund'.
Discussion
On the one hand, as tchrist and Edwin Ashworth have said in the comments, modern grammar does not distinguish between gerunds and present participles. For example, CGEL has whole sections whose entire purpose is the defense of the proposition that those two are not distinct (pp. 82-83 and 1220-1222).
On the other hand, CGEL also says this (1220-1221; the asterisk, '*', means that what follows is not acceptable English):
So: if the subject can be in the genitive, then what we have is a gerund. Now consider your sentence:
[1] We’re depending on his/him/*he finishing the job by Friday.
This is just like CGEL's [39i], and thus finishing is a 'gerund'.