Active vs passive vocabulary

I just finished off listening , and also reading the transcript, the last English podcast about active and passive vocabulary. I really enjoy it a lot as I felt as if Steve and Alexo were talking about my experience learning English. I think I can read any type of book in English. Actually I have read a lot of them without any problem. But when it comes to having a conversation I , sometimes, find myself struggling in using a word that I have read several times and I am still not able to use it in a comfortable way. Interesting. And, I have lived in Canada for almost 7 years. I consider myself to be quite fluently in English.