"If you have questions, call me personally."
Translation:Falls du Fragen hast, ruf mich persönlich an.
If you use "Sie" in the first part of the sentence, you have to use it when giving the order in the second part of the sentence: "Falls Sie Fragen haben, rufen Sie mich persönlich an"
I estimated that "Falls ihr Fragen habt, ruft mich persönlich an", "Falls Sie Fragen haben, rufen Sie mich persönlich an", "Falls du Fragen hast, ruf mich persönlich an" are the three ways for this sort of translation
du and ihr are second-person pronouns, and German has a proper imperative (command form) for the second person -- this doesn't include the pronoun, as in English ("call me" not "you call me" or "call you me").
Sie works grammatically like a third-person pronoun (like "they"), and German doesn't have a third-person imperative. So what it used for commands addressed to Sie is the subjunctive, and that doesn't allow you to omit the pronoun.
If you want to be very literal, then rufen Sie mich an! is something like "may They call me!" (using "may" to represent the subjunctive mood in this example).
Because ob means "if" as in "whether" (e.g. "I don't know if he's coming or not / I don't know whether he's coming or not") and not "if" as in "supposing, in the case that".
My "Falls du Fragen hast, rufe mich persönlich an" was rejected; DL preferring "ruf" over "rufe". Are not "ruf" and "rufe" interchangeable?
Are not "ruf" and "rufe" interchangeable?
Not entirely. They're both standard German in theory, but in practice, the e-less form is overwhelmingly more common in my experience.