The difference is very subtle. When you say “There were just six of us” you are merely announcing how many people there were. Then maybe you can start enumerating those people, (i.e “There were just six of us; me, alexander, sofia, ivan...” and so on). However, the main focus on this type of sentence is on ‘us’ and not on ‘who specifically”. “US” can be a nationality, a team, a race, or any other unifying attribute that merges certain group of people along with you. For example: “When I was little I went abroad to study in Britain, and surprisingly on our school there were six of us.” “I didn’t know anyone else knew about the new law, but can you believe it? On the bar I went last night there were six of us who knew”. On the other hand, “There were the six of us” it is implied that the six people are already known by the listener. In other words “the six of us” are individuals and not a group as in the previous sentence. To put it simpler, by adding “THE” you are referring to something specifically. For example: A car, can be any car; THE car, is a specific materialization of the concept “car”: The car of my friend, the car that can drive 20 miles, the car that talks, etc. Hope this helps!

Entendido es cuando la información dada ha sido ha sido percibida claramente por alguien o por algo. Por ejemplo: “El tema de hoy ha sido entendido por los estudiantes” “Este lenguaje ha sido entendido por el programa” “Luego de esta explicación: ¿Queda entendido los puntos claves?” Por otro lado, entiendo es una respuesta que da alguien cuando entiende algo (cuando percibe con claridad alguna información). Por ejemplo: Juan: “Los números primos son aquellos que únicamente tienen dos divisores: él mismo y el 1.” Adriana: “Entiendo.” Otro ejemplo: “Si, cuando veo la película entiendo porqué los Puertorriqueños son como son, pero no entiendo cómo han hecho música tan bonita”. Espero esto ayude.

Hi, I think, if done in proper context he could understand, but it isn't natural nor correct. The proper (and easier way) would be: "Who do you want your best man to be?". The way you are writing it, seems like the question is regarding the bridegroom. As if you are asking him if he wants to be his own best man. I hope this helps.

"Finalmente, tampoco se ha formado gobierno en España tras la segunda investidura." Finally, there hasn't formed any government in Spain after the second investment. "La situación se complica y aparece incluso el fantasma de unas terceras" The situation complicates and even the ghost of any thirds appear.

I agree with Marta. Go out or get in and interact with the language. Meet different kinds of people who speak English in all kinds of ways. Watch a movie, a show or simply a cartoon! The key is to enjoy it even if you don't understand a darn thing! Good luck!