มานานเท่าไหร่แล้ว

how long have you been ...

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phrase Rare #13,190
how long have you been ... Asks how long an action or situation has been continuing up to the present. The verb or activity usually comes before this phrase.
TH: คุณทำงานที่นี่มานานเท่าไหร่แล้ว?
EN: How long have you been working here?