Learn Farsi: استاد می‌بایست این فرمول حساس را می‌خواند. - The professor should have read this delicate formula.

To express an unfulfilled past obligation ('should have read'), Farsi pairs می‌بایست (or بایست) with the past continuous verb. Since the professor didn't actually read it, we use the past continuous می‌خواند to show what was supposed to happen in the past but didn't.

Could I use بایست without the می‌ prefix for 'should have'?

Yes! Both بایست and می‌بایست are correct and mean exactly the same thing in this structure. Adding the می‌ prefix to the obligation word is just a common stylistic choice when talking about the past.

Why does the direct object marker را come after حساس and not right after فرمول?

The marker را must always follow the entire noun phrase that acts as the specific direct object. Here, the complete object is 'this delicate formula' (این فرمول حساس), so را is placed at the very end of that phrase.

Does می‌خواند just mean reading the words out loud?

Not necessarily. In Farsi, the verb خواندن is very versatile. While it means 'to read', in an academic context like looking at a math or chemistry formula, it implies studying, analyzing, or carefully going over the over the material.