You cannot vary this question order 1, 2, 3, 4, 5.  It is not possible, for example, to put # 3 - the subject 'he', before  #2 - the auxiliary verb, didn't. The order 1,3, 2,4,5 is simply incorrect. This is why you cannot say 'Why he didn't like the movie?'.   The word order is wrong.

Likewise, 'Why you didn't study the lesson again?' and 'Why she didn't like her math class?' are wrong because the word order is wrong. The auxialiary verb 'didn't' has to go before the subject - not the other way round.

The correct sentences are

Why didn't you study the lesson again?

Why didn't he like the movie?

Why didn't she like her math class?

Just remember 1,2,3,4,5 - Question word, auxiliary verb, subject, main verb, object/rest of sentence - and you won't go wrong.

I hope that helps.

Questions have to follow this order:

1. Question Word ---------- Why

2. Auxiliary Verb ----------- didn't

3. Subject------------------- he

4. Main Verb----------------  like

5. Object + rest of question-the movie

Hello,

What about this sentence. Is it correct? Why?

"Who first stepped on the moon?"

The answer from SUKI are very specific and helpful to me, I alway made this kind of mistakes that put the subject before the auxiliary verb, now it is very clear.

Thank you, Su.Ki.

I think that correct is also :

Why did you not study the lesson again ?