-ing form

An -ing form is the form taken by a verb with -ing added to the infinitive (obeying the basic spelling rules, such as removing the final e (have - having) or doubling the final consonant (shop - shopping), where necessary. When used as verbs, adjectives or adverbs, they are often, possibly mistakenly, referred to as present participles. When used as nouns, they can be referred to as gerunds. But those terms are sometimes misleading.

One of the very few strict rules in English, i.e. no exception (or debate), is that of the need to use the -ing form of a verb, not its infinitive, after all prepositions. The only possible complication is deciding whether that to in the sentence is a preposition or an infinitive marker, in which case it obviously goes with an infinitive.

Apart from the obvious monosyllables, such as sing, king, etc., not all words ending -ing are gerunds or participles: ceiling, whiting and duckling.

Spelling rules

 * Most verbs add -ing to the infinitive form. See Default below.
 * Verbs ending in e replace e by ing: like - liking; recieve - receiving
 * Verbs "dye" and "singe" don't drop the e: dyeing, singeing /ˈsɪndʒɪŋ/
 * In British English the "-ing" form of "age" is spelled "aging" or "ageing"


 * Verbs ending in one stressed vowel + one consonant (except w, x or y) double the consonant and add -ing: planning; stopping; referring; controlling;
 * This rule also applies to the verb "program", even if it doesn't end in a stressed syllable: programming
 * In British English, the letter "l" is doubled after a single unstressed vowel: levelling - leveling; travelling - traveling


 * Verbs ending in -c add king: picknicking; trafficking;
 * Verbs ending in ie change their ending to "ying": die - dying; lie - lying; tie - tying;


 * Default. All other verbs add -ing.
 * Ending in one or more vowels (except final e): mooing; skiing;
 * Ending in two or more consonants: depending; pushing; starting;
 * Ending in two or more vowels + one consonant: explaining; raining;
 * Ending in one unstressed vowel + one consonant: editing; offering;
 * See exceptions above (program, and verbs ending in "l")
 * Ending in w, x or y: playing; enjoying; copying; flying; showing; taxing;

Present participle
See main article present participle.

Gerund
See main article Gerund.

A gerund is a noun, corresponding in most cases to an action or activity, such as smoking, reading or many sports (not games), such as swimming, weightlifting and fencing.

-ing form or infinitive

 * There are a number of verbs that can be followed by an -ing form or an infinitive, but there may be, in some cases, differences in meaning:
 * like (love, hate, prefer, can't stand/bear). I like to play; I like playing
 * start (begin, stop, continue). I started to eat; I started eating
 * allow (permit, forbid)
 * see (watch, hear)
 * forget (remember)
 * try (intend, propose, advise)


 * There are a number of verbs that are normally followed by an -ing form:
 * admit
 * can't help
 * enjoy
 * feel like. I feel like dancing
 * finish
 * look forward to
 * mind


 * There are a number of verbs that are normally followed by an infinitive:
 * expect. I expect to go
 * hope
 * learn

Used to
See main article Used to.

One especially clear case is the difference between used to + infinitive vs be used to + -ing form, at least regarding the structure (i.e. with be + used to'' we use the -ing form).

Adjectives
There are a number of frequently used adjectives that students should be made familiar with: amusing - annoying - boring - disappointing - exciting - frightening - interesting - shocking - surprising - terrifying	- tiring - worrying. Care should be taken to avoid eventual confusion between, for example, be worrying and be worried, and, most especially be bored vs be boring, as in I'm bored...