I am still a bit confused when it comes to distinguishing gerund and -ing participles. Are there any authentic texts with the key available to practice.
The gerund is an -ing form that can be used - with or without complements, objects, or modifiers - as one of the following sentence components: (the gerund and any complement or modifier is parenthesized )
Sentence subject: (cooling cloth this way) makes it more rigid
Sentence direct object: it meant (cooperating with the moderates)
Subject complement: the result is (an aping of genre conventions )
Prepositional object: survives by (acting as a jailhouse lawyer)
Attributive modifier of a noun: they started (a bidding war)
The progressive participle is used with the auxiliary verb BE and often describes something of limited duration, involving repetition, or occurring or existing at the time of speaking.
Someone's knocking at the door.
I'm talking to you.
[This is a quite cursory chat on the -ing words - I hope it helps a bit. ]