Hi Allie E!
In Chinese, the verb 在 is used to express the existence in a place. English does not have a verb exclusively for this purpose, and instead uses "to be" with a preposition. In Chinese, 在 can cover both of these roles.
Basic structure: Subject + 在 + Place.
Additionally, the verb 有, can also express existence. This is similar to saying "there is" or "there are" in English.
Basic structure: Place + 有 + Object.
This is a little more complex though since 有 can also be used to mean "to have" and this structure is as follows.
Basic structure: Subject + 有 + Object.
In your English sentence, although the meaning is the same, the grammar is actually wrong when compared with the Chinese sentence. The main subject in your sentence is 中学 "middle school" and not 我们 “our", as "our" is the possessive pronoun and "village" is the object of the preposition. But again, this translation is okay, but not exact when looking for the correct grammar.
The direct translation, although crude, would be something like "Our village inside has a middle school"...But do remember that Chinese sentence structure is a little different, so in English, this sentence would be re-written as "Our village has a middle school inside of it."
Thus we would use the second stated form of 有, meaning "to have"
Subject + 有 + Object.
Our village (村) has (有) a middle school (中学) inside of it, but the "inside of it" grammatically belongs to the village so we need to move the words around in Chinese to be 村里有 "...village inside has..." and then add the other parts of the sentence:
- 我们 (our)
- 一 (a),
- 所 (measure word for schools)
中学 (middle school)
which becomes 我们村里有一所中学, the correct sentence.
If you wanted to use 在, you would need to change the sentence to something like, 我们在村里的中学. We are at our village's middle school. This is how you use 在.
I hope this answers your question!!!