Hola Johan

I imagine you are referring to this sentence in that lesson:

"Yo digo lo que pienso" (I say what I think)

Here you need to see "lo que" as a unit, not just as "lo" individually. Here is the lesson you want:

Using lo que = what, which, that which, the thing that (relative pronouns)

Hope it helps.

Inma

Hola Sue

Semi-regular verbs are those that undergo a "stem change" in some tenses, but they maintain the regular endings. For example: empezar=to start -present tense (yo empiezo, tú empiezas, él empieza...). However totally irregular verbs are those that ungergo a "complete change" both in the stem and the endings. For example: ir=to go -preterite (yo fui, tú fuiste, él fue...).

I hope this made it a bit clearer.

Saludos

Inma