if you know how to say a declarative sentence, it will be quite easy. just replace what you want to demand by an interrogative for example: declarative sentence: 我叫Tom (my name is Tom) we will question about Tom interrogative: 我叫什么？（什么means what ofc normally you would say 你叫什么 this is the problem of subject） declarative: 他九点回家(he gets home at 9 o'clock) we will question about 9 o'clock interrogative:他什么时候回家？（什么时候 means when) when does he get home? declarative: Tom住在paris (Tom lives in paris) we will question about Paris interrogative:Tom住在哪儿？（哪儿means where） where does Tom live? declarative: Tom喜欢这本书，不喜欢那本书（there are two books and Tom likes this one, not that one） we will question about "this one" interrogative: Tom喜欢 哪一本书？（哪一+ 量词---只/个/本/张 etc means which/which one） which book does Tom like? declarative: Tom坐火车去的paris（Tom goes to Paris by train） we will question about "by train" interrogative: Tom怎么去的Paris？（怎么 means how） how does Tom go to paris? about reason: imagine: you need arrive at school before 8 o'clock but you car is broken so you are late and you teacher demand to you: 你 为什么 迟到了？ (为什么 means why) why were you late? you say: 因为我的车坏了。（because my car was broken. 因为 means because） now you can see, the question in chinese is very easy: just replace what you want to demand by some interrogative and dont change other part of the sentence. look at last example about reason, it's a little different. but the rule is the same. why does we put the "为什么" after the subject 你？ because normally, the response would be "因为我....." after 我 it is the reason so we replace the part after 我 by 为什么（ofc dont forget to change the subject） so remember the rule is: replace what you want to demand by the interrogative that's all. one more: if you want to highlight what you demand, you could put those interrogative at the beginning of the sentence for example, 你什么时候回家？ when does you get home? we can also say: 什么时候你回家？ highlight 什么时候 你为什么迟到了？ why were you late? 为什么你迟到了？----highlight 为什么---------I really really want to know the reason.

What=什么 As an object, in Chinese we usually put "what" behind the verb. E.g. What do you want to say?你想说什么？ As a subject, we put it in front of the sentence. E.g. What makes you so upset?什么让你这么沮丧？ Where As an object, means 哪里, quite like the "what" E.g. Where do you want to go?你想去哪里？ As an adverbial modifier, means 在哪里, usually we put it before the verb, or even the subject. E.g. Where can I smoke?我可以在哪里抽烟？or 在哪里我可以抽烟？The former is better. When As an adverbial modifier, means (在)什么时候 or （在）几时, sometimes we omit 在. The usage is quite like the "where". E.g. When will you divorce?你想什么时候离婚？However, in this case, we should cautiously put "when" before the subject, for it may derive another meaning. (The time you divorce and the time you had the will). How As an an adverbial modifier, can be used singly or with an adj. or adv. When single, means 怎么 or 如何, put it before the verb, but not before the subject. E.g. How do you learn English?你怎么学英语？ When with adj. or adv., means 多么~ or 多~ . Basically we put it after the verb or object but adhere the adj. or adv.. E.g. How deeply do you love him?你爱他有多深？As you may find, we add "有" before "how deep" to make the sentence more smooth.

hello. i can't get your meanings very well. what( shen me 什么 in chinese)= you want to know something,just like what's your name? 你的名字是什么？（ni de ming zi shi shen me?)； when( shen me shi hou 什么时候 in chinese)= you want to know time.e.g. when will you go home? 你什么时候回家？（ni shen me shi hou hui jia?) where( na li 哪里,shen me di fang什么地方in chinese)=you want to know someplace, e.g. where is my book? 我的书在哪里?/我的书在什么地方？(wo de shu zai na li? /wo de shu zai shen me di fang?) how( zen me yang怎么样 ,ru he如何)= you want to know method/situation,e.g. how can i get there?我怎样才能到达那里？wo zen yang cai neng dao da na li? (method) how is your mum? 你妈妈身体怎么样？ni ma ma shen ti zeng me yang?( health situation)