There are no articles in Russian. You should guess type of subject by context or by additional explanation. Or by asking a questions like: "What house are you talking about?" We don't use "to be" in present tense except in some special cases (for example when we want to make an emphasis on a part or a component of whole object: "в доме есть подвал" - "There are a basement in the house"). But we use it in past and future tense: "Это был дом", "Это будет дом" And of couse when we learn different language we should learn ways of thinking and communication of native speakers from very beginning

Craig, yes, we don't use it. _Sometimes_ we want to use it. And there are several ways to do that. But in simple staments like "this is a house" or "John is a teacher" we omit it.

We dont use articles. I dont know what is it :-)

My advice: don't compare Russian and English. These languages are absolute different, there are very many things that unnatural for English-speakers in Russian and for Russian-speaker in English. Not only articles and to be :) For example, in Russian we always use double negotiations and "Nobody wants" sounds really strange for the Russian English-learners.

Yes, as a rule the verb "быть = to be" is absent in present time. We can say "Это есть дом", but it sounds a bit unnatural. The usual phrase is " "Это дом". In the past and future, the verb "to be" is present - "Это был дом". "Это будет дом". About the articles the = (именно) этот a = один из