Spanish language Q&A Forum

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.

My understanding was that the accent falls on the penultimate syllable unless another syllable is accented. Given that where does the accent fall on “peinar”?  Is it not split into pe in ar?  

Neither of these are phrased in the passive and the second sounds like it could be a command. If they had been phrased "what vegetables are needed?" and "first one buys fresh vegetables", then I could see. Are there reasons that my answers are wrong??

Here's what I put:

Lidia] Ah pues dime, ¿qué verduras necesitan?

[Sonia] Mira, primero compra verduras frescas 

Hello,

I have had a lot of difficulty distinguishing between choosing whether a verb is in the imperative or subjunctive in some complex sentences. 

Is there a clear way to determine this? 

For example, I'm not sure which of the 3 categories in the lesson, this sentence I came across and failed to identify as subjunctive, would fall under: 

"Al final será el consumidor quien pague la factura."

I would have used the present or imperative here more so. (Would it be possible?)

Thank you,

Nicole