1.
A verb whose conjugation follows a different pattern is called an irregular verb.
2.
As was stated above, you can tell if a verb is irregular by putting it in its simple past and past participle forms; if it doesn't end with –d or –ed, then it is an irregular verb.
3.
An irregular verb is one that does not form its simple past tense or its past participle by adding "-ed" or "-d" to the base form. Irregular verbs contrast with regular verbs, which form the simple past tense and past participle by adding "-ed" or "-d."
