Spanish language Q&A Forum

This seems to me to be too ambiguous (or maybe too subtle) to be used in a lesson.

Gabriel no podía meter las llaves en la cerradura anoche.
Carlos couldn't put the keys in the keyhole last night.

Without additional information, it appears that it could be either way, depending on the reader’s interpretation.

I have had this problem for a while, and no Spanish speaker can readily explain it:

In English, an adjectival form can only describe a noun; for a verb, you must use the adjectival form. The only exception of which I know is "I am well." Because so few English speakers have good grammar these days, "I am good" has become a colloquialism that is acceptable. But one can never say "I cook good" or "He lives happy".

But in Spanish, I see this all the time though Spanish speakers also acknowledge the rule that adverbs, not adjectives, describe verbs. In this lesson, I just saw it again: 

Espero que vivas feliz en tu apartamento nuevo.

The quiz question was “muchas veces estoy triste” being translated to “I am often sad”. Why would that not be “A menudo estoy triste”?

Newbie here: I’ve always been told that Spanish accent is usually on the penultimate vowel, and only the exceptions need an explicit tilde mark. 

However, there are conjugations, like actuéis where the accent mark is on the penultimate vowel. I would have thought that the accent wasn’t needed anymore. Any place I could go to with a fuller explanation?

Thanks.