1. Preterite Tense – Ir & Ser
El pretérito – Ir y ser
Preterite Tense – Ir & Ser

2. Ir and Ser have the same forms in the Preterite Tense
fui
I went
fuimos
We went
fui
I was
fuimos
We were
fuiste
You went (familiar)
fuisteis
You went (plural)
fuiste
You were (familiar)
fuisteis
You were (plural)
fue
You went (formal)
He/She went
fueron
You went (plural)
They went
fue
You were (formal)
He/She was
fueron
You were (plural)
They were

3. The context of the sentence will usually tell which verb is being used.
Yo fui al supermercado esta mañana.
I went to the supermarket this morning.
Fue una película muy aburrida.
It was a very boring movie.