Basic Conversations

Imagine your father is a diplomat stationed in Spain and you will attend public school there. You will need to learn some basic conversation phrases to socialize with your classmates. Here are some basic phrases to get you started.
hola is a common way to greet someone hola means hello or hi
buenos is only used with días so it would be buenos dias and this means good morning.
the other two (good evening and good night)
both start with buenas, so its buenAs not buenOs
good evening is buenas tardes
good night is buenas noches
here is a site to provide you with more info on greetings: 

http://http://www.lingolex.com/swom/wom-greetings.htm