First: Wyzant does not appear to support the use of Chinese characters, so I apologize that I can only reply using 'pinyin'.
Yes, Chinese is a tonal language, but it's very easy to know if a question is being asked.
There are FOUR ways in Chinese to do this:
1) The first is to use the character 'ma' at the end of the sentence. When the word 'ma' is placed at the end of a STATEMENT, it automatically makes it a question. For example, "Ni shi mei guo ren ma?" = Are you American?
2)The second is to use verb duplication and the word 'not': 'bu' or 'mei' (depending on the situation). Here, you basically say "You are or are not American?" = "Ni shi bu shi mei guo ren?" or "You have or have not money?" = "Ni you mei you qian?"
3)The third is to use a question word, just like in English, i.e. "What time" in Chinese is: Shenme shihou? When you hear a question word structure, you automatically will know that the person is asking a question.
4) Contrary to popular belief, you can also just raise the tone at the end of the sentence, just like in English. Chinese is not just a tonal language; it is also a contextual language. For this reason, it is easier for a Chinese native to understand what you are saying when your sentence is longer. Why? The longer the sentence, the less important the tones are because they will know what tones you WANTED to say simply based on the context. For example, if you say the word 'ma' with the wrong tone, no one will know you are referring to a horse. But if you are pointing at a horse and say, 'ma!', even if the tone is wrong, they will know you are trying to say 'horse', and not 'mother', not 'question', and not 'to scold'. In the same vein, if you ask someone a question, and raise the tone at the end of the last word, everyone usually knows what tone you intended to originally say, and will know it is a question. This technique is used by Chinese natives too, particularly as English becomes more and more popular in the world.
Hope this helps!