For example, after “dream” you see “dreamed or dreamt,” which means both are acceptable. In this case, there’s no past participle form listed, which means “dreamed” and “dreamt ...

For example, the day after you decide to grin ... Dictionaries list past-tense and past participle forms for every irregular verb. So you can always look them up — if you know how.

The first part is often the verb avoir ‎- ‎to have and the second part is the past participle.‎ For example, j'ai mangé un sandwich - I have eaten a sandwich. You take the form of avoir you ...