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(1) It was not until when he failed the math test that he decided to study hard

(2) It was not until he failed the math test that he decided to study hard


Are both (1) and (2) grammatically correct? Do they each have the same meaning ?

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Hoony until when

We don't use this combination of words. The meaning of 'when' is included in the meaning of 'until'.

HoonyAre both (1) and (2) grammatically correct?

I would not consider "until when" correct. "when" is completely redundant. This may be more a matter of word usage than a matter of grammar.


There is an exception when you ask a question.

"Until when?" can be used as an alternate way of asking "For how long?"

— I'm going on vacation tomorrow.
— Until when? / For how long?

CJ