Did you know that ‘swum’ and ‘swam’ are both correct forms of the verb ‘swim’? This article explains how to use irregular verbs, such as ‘swim’, correctly as their role in a sentence changes.

This article explores the tricky transformations of verbs as they move from plain form, to past tense form, to past participle form. In the final instalment of this series, we will also cover the present participle form of verbs.

Past Participle Form

When the verb appears with (and after) the verb to have or to be, it takes what is called past participle form. It gives the verb a passive voice.

Regular Verbs in Past Participle Form

Regular verbs have the same form in past tense and past participle form. The plain form ‘walk’ becomes ‘walked’ in past tense and past participle form. You notice that in past participle form ‘walked’ needs a preposition — you have to be walked somewhere:

Past tense form is I walked; I have walked; I had walked.

Past participle form is I was walked to (the shops); I will be walked alongside (the river); I am being walked over (the bridge).

Irregular Verbs in Past Participle Form

Some irregular verbs take the same form as their past tense form. The plain form ‘buy’ is an irregular verb that becomes ‘bought’:

Past tense form is I bought; I have bought; I had bought.

Past participle form is I was taught (by a teacher); I will be taught (on Wednesday); I am being taught (about Ancient Greece).

You will notice the need for prepositions again. In the above example, they are ‘by’, ‘on’ and ‘about’ respectively.

Some irregular verbs undergo another transformation from their past tense form. ‘Sing’ is an example of this transformation; watch it go from plain form to past tense to past participle form below:

I sing on TV; I sang on TV; I have sung on TV before; the song was sung on TV.

Here are some more examples:

• I write the words; I wrote the words; I had written the words; the words had all been written before.
• I forget the words; I forgot the words; I had forgotten the words; the words had been forgotten.
• I break the back of it; I broke the back of it; I had broken the back of it; the back of it had been broken.
• I sink the boat; I sank the boat; I have sunk my boat; the boat was sunk.

Now I return to the example we started this article with: what about ‘swim’, ‘swam’ and ‘swum’?

I swim in the pool; I swam in the pool; I have swim in the pool many times; the pool has been swum in.

We hope this article has been helpful in explaining the tricky transformations of irregular verbs.