Generally, “a” is used before a singular noun that is not specific or not known to the listener. For example, “I live in a house” means that I live in one house, but it is not important or clear which house it is.
“The” is used before a singular or plural noun that is specific or known to the listener. For example, “I live in the house on the corner” means that I live in one house, and it is clear which house it is.
Sometimes, “a” and “the” can be used interchangeably for places, depending on the context and the meaning. For example, “I went to a park yesterday” means that I went to one park, but it does not matter which park it was. “I went to the park yesterday” means that I went to one park, and it is assumed that the listener knows which park it is.
There are also some cases where “a” and “the” are not used at all for places. For example, we do not use “a” or “the” before the names of countries, cities, continents, or streets. We also do not use “a” or “the” before some common places like school, work, home, or church, unless we want to specify something about them. For example, we say “I go to school every day”, but we say “I go to the school where my sister works”.
