Here are strict translations of the two sentences. (If talking to one person, use 'X 씨에게 / X 씨가' instead of 여러분에게 / 여러분이, where 'X' is the person's name) 1. I have something to ask you. => 여러분에게 물어볼 게 있어요 or 여러분께 질문이 있어요 (I have question for you). 2. I have something I need you to do please. => 여러분이 해야 [하셔야] 될 게 있어요. ('하셔야' is more respectful than '해야') You could also say it a little differently in your situation. 1. 여러분이 설문지에 답변을 해 주셨으면 좋겠어요 (I would like to ask you to fill out a questionnaire). 2. 여러분이 (제게) 한 가지 해 주셨으면 좋겠어요 (I would like to ask you to do something for me).