Learn Farsi: اگر بنایی را ببینی که یک گنبد بزرگ روی آن است، خوشحال می‌شوی. - If you see the monument that has a large dome on it, you will be happy.

In Farsi, relative clauses with prepositions require a resumptive pronoun. Instead of saying "on which is a large dome," Farsi uses ke to connect the clause, and then uses a regular pronoun (ân) with the preposition (ruye) later in the phrase. It literally reads "that a large dome is on it."

If the translation says "the monument", why does the Farsi say banâyi with an -i suffix, which usually means "a monument"?

The -i at the end of banâyi is the restrictive -i, not the indefinite article. It acts like a pointer saying, "I am about to specify exactly which monument I mean." Because the ke clause makes it a specific, defined monument, it still takes the definite direct object marker râ.

Why are there two different verb forms, bebini and mishavi, for these actions?

This is a standard "real conditional" sentence. The "if" clause (agar...) uses the subjunctive mood (bebini) because the action of seeing it is still hypothetical. The result clause uses the present indicative (mishavi) to express the certainty of becoming happy if that condition is met.

Why does the Farsi use ast (is) rather than a form of dâshtan (to have) for "that has a large dome"?

While English often uses "has" for descriptions like this, Farsi frequently describes location by stating something "is" somewhere. The phrasing literally means "a large dome is on it," which is a very natural way to express this in Farsi.