Start a question with あのう

あのう gets the other person's attention before your question, so the question does not come out of nowhere. It usually has a comma after it: あのう、すみません. It is not the あの of あの ひと, “that person over there”, from L2. The two are written the same, but that あの stands in front of a noun and points at something. This one stands alone at the start of what you say.