Learn Farsi: مرد پیر در حالی که داشت سازدهنی می‌زد، گدایی می‌کرد. - The old man was begging while playing the harmonica.

در حالی که (dar hâli ke) specifically means "while" or "in the state that." It emphasizes two ongoing actions happening at the exact same time. While you could technically use وقتی که (vaghti ke - when), در حالی که is much more natural here because it paints a picture of the old man doing both things simultaneously.

Why is داشت separated from می‌زد by the word سازدهنی?

In the Farsi past continuous tense, the auxiliary verb (داشت) and the main verb (می‌زد) usually bracket the direct object. Instead of keeping the verbs together like in English ("was playing the harmonica"), Farsi wraps the verb parts around the object: داشت سازدهنی می‌زد (literally "had harmonica playing").

Why does the first part of the sentence use داشت (past continuous) but the second part just uses می‌کرد (past imperfective)?

The auxiliary داشت is often used to add vividness, emphasizing that an action was "right in the middle of happening." It's very common to use it in a dependent clause to set a vivid background scene (در حالی که داشت...), and then drop it in the main clause (گدایی می‌کرد). The می prefix on می‌کرد is already enough to show the action was ongoing, so repeating داشت isn't necessary.

Why is the verb زدن (to hit) used for playing the harmonica?