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

The correct phrase is "How long did you know?" This is the commonly used and grammatically correct way to ask about the duration of time someone has known something or someone.

Last Updated: March 25, 2024

how long did you know?

This phrase is correct and commonly used in English.

This phrase is used to inquire about the duration of time someone has known something or someone. It is a grammatically correct question in English.

for how long do you know

This phrase is not correct in English.


Alternatives:

  • For how long have you known?
  • How long have you known?
  • How long do you know?
  • How long have you known for?
  • How long have you known that?

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