Question

Did I choose the right answer?

Choose the correct conjugation of the verb between parentheses.

Cuando mi hermano me (llamar) ayer, no le contesté.
llamo
llamó
llame (<— My answer)
llama

Answer 1

Hello, @lexismith !
If it was about *yo*, then *llame* (with accent on *e*) would be right.
But this is referring to *mi hermano* (= "my brother"), that is *el* (with accent on *e*). So the right answer is actually *llamo* (with accent on *o*).

Here's the pattern:

PRETERITE for verbs whose infinitive ends in -AR (like *llamar*)

(yo) -- llame (ending: -e)
(tu) -- llamaste (ending: -aste)
(el/ ella/ Ud.) -- llamo (ending: -o)
(nosotros/ nosotras) -- llamamos (ending: -amos)
(vosotros/ vosotras) -- llamasteis (ending: -asteis)
(ellos/ ellas/ Uds.) -- llamaron (ending: -aron)

Hope this helps!
Blessings