"how long do you know it?" vs "how long did you know?"

Question

"how long do you know it?" vs "how long did you know?"

The correct phrase is "How long did you know?" This is the correct past tense form of the question. The other phrase, "How long do you know it?" is incorrect because it mixes present tense (do) with past tense (know).

Last Updated: March 25, 2024

This phrase should not be used as it is grammatically incorrect. When asking about the duration of knowing something in the past, the correct form is to use the past tense.

This phrase is used to ask about the duration of knowing something in the past. It is the appropriate way to form this question in English.

Answer 1

how long do you know it?

This phrase is incorrect. It mixes present tense (do) with past tense (know).

Answer 2

how long did you know?

This phrase is correct and is the past tense form of the question.

"how long do you know it?" vs "how long did you know?"

how long do you know it?

how long did you know?

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