Learn Farsi: هر رستوران باید استانداردهای بهداشت را رعایت کند. - Every restaurant must observe hygiene standards.

The word har means "every" or "each." Just like in English, it must be followed by a singular noun. Furthermore, har attaches directly to the noun without an Ezafe. So, "every restaurant" is strictly har resturān.

If I wanted to use hame-ye (all of) instead of har (every), how would this sentence change?

To say "all restaurants", you would use hame-ye resturān-hā (notice the Ezafe linking them and the plural marker -hā on the noun). Because the subject is now plural, you would also need to change the verb at the end of the sentence to the plural form: re'āyat konand.

Why does rā come after behdāsht instead of right after the plural estāndārd-hā?

The object marker rā points to the entire specific direct object. Here, the object isn't just "standards", it is the entire phrase "hygiene standards" (estāndārd-hā-ye behdāsht), which is linked together by an Ezafe. The rā must always wait until the very end of that connected noun phrase.

Why does the verb re'āyat kardan appear as konad rather than mikonad?

The sentence uses bāyad (must). In Farsi, verbs following bāyad must take the subjunctive form. For the compound verb re'āyat kardan (to observe or comply with), we form the subjunctive by dropping the indicative prefix, leaving us with .