Which are correct:<br/><br/><span style="color:#ff0000;">1) Have you known someone to lose all his money in Las Vegas?</span><br/><span style="color:#ff0000;">2) I have known someone to lose all his money in Las Vegas.</span><br/><br/><span style="color:#ff0000;">3) I knew someone to gamble a lot.</span><br/><br/><span style="color:#ff0000;">4) I know someone to gamble a lot.</span><br/><br/>Gratefully,<br/>Navi.