what
01
何, どの
used in questions to ask for information or for someone’s opinion
例
What did you have for breakfast?
朝食に何を食べましたか？
02
何, こと
used to represent an entire idea, concept, or clause within a sentence that acts as the subject or object of the verb or preposition
例
I didn't understand what you said.
あなたが言ったことが理解できませんでした。
what
01
どの, 何
used to introduce a clause or phrase in a general manner
例
I don't know what time it is.
今何時か分かりません。
