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