consider this sentence:
I saw him driving the car.
I know it is made from two sentences
1.I saw him
2.He was driving the car
in the second sentence it is obvious that driving is a verb, but when you join them what is "driving": a verb or an adverb or an adjective or a noun? if it is a verb, it should have a subject and "he" is used as him.It is really messing with my mind.