From Teflpedia
Disambiguation: singing

Sing is an English verb.

Sing is an irregular lexical verb; it has the third person form "sings", the -ing form "singing", but an irregular preterite "sang", and an irregular past participle "sung". The latter two forms may be over-regularised to *"singed".

It is also possible for students to confuse sing with sign or singe, resulting in odd requests to "sing a contract".