Irregular verbs

    The past tense and past participle of regular verbs end in -ed:

     

    Infinitive Past tense Past participle
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    rain rained rained
    walk walked walked
    work worked worked

     

    Some verbs, however, are irregular.

     

    Infinitive Past tense Past participle
    be was/were been
    eat ate eaten
    have had had
    know knew known
    put put put

     

    When we form the present perfect, past perfect or the passive, we need the past participle of the verb:
    Present perfect: "I haven't had breakfast yet."
    Past perfect: "She had known him for only two weeks."
    Passive: "Then I discovered that the laptop had been stolen."

    With some irregular verbs, all three forms are the same: for example, put and hit.
    Sometimes the past tense and the past participle are the same, but different from the infinitive, such as have — had.
    And sometimes all three forms are different: know — knew — known.

    These verbs can be regular or irregular, particularly in British English:
    burn — burned or burnt
    dream — dreamed or dreamt
    lean — leaned or leant (UK)
    learn — learned or learnt (UK)
    smell — smelled or smelt (UK)
    spell — spelled or spelt (UK)
    spill — spilled or spilt (UK)
    spoil — spoiled or spoilt (UK)

    It is really best if you learn the irregular verb forms by heart. Click here to download an extensive list of them.