Why don't you ask -------- to help you?

someone
这里虽是问句,但请求某人帮助时比较明确的,在对象明确时即使是问句一样用someone
再如
would you like some juice?
再问： 那如果是 Why didn't you buy ______ for yourself? 该是something还是anything呢？
再答： 这里选 anything，解释差不多，这里是问句，且对象不明确，要买什么不知道。