It has been a long time since I have met you You don’t need the second HAVE. It has been a long time since I met you - you’d probably use this sentence in a letter to someone. You wouldn’t be talking to the face to face at that exact time. And you’d be referring to a time in the past when you met and you’d be suggesting that maybe you should meet again soon. Maybe you miss them. It has been a long time since I met you. (see above) It had been a long time since I had met you. You don’t need to say the 2nd had. But you DO need a 2nd action. The past perfect (had) is used to talk about an event which happened BEFORE another event. It had been a long time since we met, WHEN we saw each other again... see the following link for further info. http://www.englishpage.com/verbpage/pastperfect.html