Hola Ana, Silvia, e Inma -
In your lesson Conjugate stem-changing-ir verbs (e > i) in the preterite tense in Spanish (El Pretérito Indefinido) - I am wondering if it might be worth mentioning that the guideline applies to the majority of verbs ending with "-e#ir" - because most of them seem to change the 'e' to 'i' in the 3rd person "pretérito indefinido" [where the # symbol denotes a consonant, or two consonants together, or even no consonant as with 'reír'] >
> i.e., almost all of them follow the pattern "servir > sirvió, sirvieron"...
... and seguir > siguió, siguieron [note that 'gu' is effectively just a consonant with its silent u]
I have come across only a few exceptions to that^ rule:
namely, the three "-cer.nir" verbs: discernir, concernir, cernir(se)... the three "-ergir" ones: sumergir, convergir, divergir... and hendir - [e.g., the third person preterite becomes él discer.nió - not discirnió].
There are also one or two [?] defective verbs which behave like that^, for example 'ellos agredieron' (they attacked), not 'agridieron'.
Saludos, David Mc
