Verbs + -ing (like / prefer / be good at)

Some verbs and phrases in English must be followed by the -ing form (also called the gerund). The most common verbs that take -ing are: like, love, enjoy, hate, and prefer. For example, we say 'I like swimming' — NOT 'I like swim'. We also use -ing after certain phrases with prepositions, such as 'be good at', 'be interested in', 'be bad at', and 'look forward to'. In all these cases, the word after the preposition is a noun form of the verb, so it must end in -ing. Spelling rules matter: for short verbs ending in one vowel + one consonant (run, swim, sit), double the final consonant before adding -ing (running, swimming, sitting). Verbs ending in silent -e drop the -e before adding -ing (make→making, ride→riding). Verbs ending in -ie change to -y + ing (lie→lying). For example: My brother is good at playing the guitar — 'playing' is the gerund after the preposition 'at'.