Sir, <br/><br/>1.I have worked here since 1992. <br/><br/>2.I have been working here since 1992. <br/><br/><br/>Are the meaning same for both the sentences. <br/><br/>"since" here works as preposition. <br/><br/><br/>3. I have not seen her since I left the school. <br/><br/><br/>In this sentence "since" works as "conjuction". <br/><br/><br/>Thanks.