Question about writing tenses

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1

<p>I am going through sparknotes 7 deadly screw ups and I'm still stuck on the tenses section.</p>

<p>Can someone explain to me the difference between infinitive, simple past, and past participle?</p>

<p>I just dont know when to use which. Do you always use the past participle with "have, had, etc."?</p>

<p>Thanks.</p>

2

<p>See Silverturtle’s guide</p>

3

<p>^^ I should look in there more often ha.</p>