Questions about Conjunctions:
Q: Why is it padres e hijos and NOT padres y hijos?
When the conjunction y occurs before a word starting with "i" or "hi", it must be written and pronounced as e.
Q: Why is it quiero venganza u honor and NOT quiero venganza o honor?
When the conjunction o occurs before a word starting with "o" or "ho", it must be written and pronounced as u.
Q: Why is it no fuimos al parque, sino que nos quedamos en casa and NOT no fuimos al parque, sino nos quedamos en casa?
When followed by a clause (a phrase with a conjugated verb) you must use sino que, rather than just sino.
Q: Why is it no sabía que ibas a llegar tan tarde and NOT no sabía ibas a llegar tan tarde?
You have to use que in Spanish when using it to link two clauses. This is different from English since the word "that" is often deleted in this context, e.g.: "I didn't know (that) you were going to arrive so late."