We mostly use 'ser' to describe how our personality or character is usually or always, something which is a fact; or how a thing is, how we describe it. On the other hand, we use 'estar' to express for example where we are, with whom, in which form. We also can express how we feel, but only in that moment. For example: 'Soy linda' indicates that I'm always cute. 'Estoy linda' indicates that I'm cute today, for some special reason. 'Soy maestra', but not: 'estoy maestra' because you are a teacher always or you aren't. Soy maestra, soy inteligente, soy modesta, soy argentina: are correct. Estoy en casa, estoy con mi hermana, estoy cansada, estoy sentada: are correct. You can not say: soy cansada, because nobody is born cansado. You can not say: estoy argentina, because you were born in Argentina, or you weren't. You can say instead: Estoy en Argentina, estoy cansada. These are correct. You see? If you have more questions, you can contact me. I hope I helped you. Bye!!

muy buena la respuesta de liliana bird te respondo en español :A)1) ser es el modo de existir (no cambia con nada); ejemplos:ser supremo (Dios),ser humano, ser dotado de vida.2)verbo irregular,en el presente: soy, eres, es, somos, sois, son, etc. B) "Dios es omnipotente","son las tres de la tarde","el precio del short es de 5 dolar",