The key to exercise solutions in chapter 11B - Experiences or things? for the textbook English File Elementary - Student's Book with authors Christina Latham-Koenig, Clive Oxenden and Jerry Lambert from Oxford University Press
Question
Look at ten verbs which take the infinitive. Which one is irregular? Which one can be regular or irregular?
Complete the sentences with a verb from a in the past tense.
Answer
a)
Forget is irregular (forgot).
Learn can be regular or irregular (learned / learnt).