The adverb clause here is <span>"since the sun came out" - it gives some information about the timing of the event.
It modifies "feels" (actually I would say that it modifies the phase "feels warmer") - this "feeling" happens since the sun came out, that's when it started!</span>
<span>Past perfect tense is used in this case. This is due to the fact that the events are not in normal chronological order. This tense is used to differentiate when the events happened and put them back into proper order.</span>
The story 'Mericans' depicts how Hispanic and Mexican immigration was having an impact on the fabric of American society and how it had created a new population which was unsure of its identity.
In some cases, the majority white population was racist towards the Mexicans while in other cases it was not.
However, even if the language and food of Mexicans was being celebrated by the majority white population, there were still several identity crises within the young.
The story gives the example of two Mexican kids who speak English and want to embrace the ways of America. However, their traditonal grandmother wants them to focus on the church, speaking Spanish and live a more 'Mexican' Life.
Such identity crises were experienced by many immigrants and still has a huge impact on first-generation immigrants from China, Pakistan, India etc
