A. ‘-ing’ form: Gerund, the form of verb ending in ‘-ing’, which can function as a noun, as an adjective, and in the formation of progressive tenses.
A1. We can use the ‘-ing’ form after these verbs: admit, avoid, consider, deny, enjoy, fancy, finish, imagine, keep (on), mind, postpone, risk, stop, suggest + ‘ing’
A2. as a noun: ‘-ing’ nouns are always uncountable nouns
A3. as an adjective.
B. The ‘-ing’ noun or adjective is formed from a verb: as an object; as an adverbial; as a clause
C. The ‘-ing’ noun can be used:
C1. as the subject of a verb
C2. as the object of a verb, verbs followed by an ‘-ing’ object
C3. as the object of a preposition
D. The ‘-ing’ adjective can come in front of a noun: amusing, annoying, boring, disappointing, exciting, frightening, interesting, shocking, surprising, terrifying, tiring, worrying
E. The negative form is ‘not –ing’