hi, pls help; this qn has been bothering me for a long time, and no one seems to be able to give me a satisfactory answer.<br/><br/>After words like thought, knew or said, do you always have to use the past tense?<br/><br/>i.e. i didn't know the earth was round <b>vs</b> i didn't know the earth is round<br/><br/>after all, the earth being round is a fact isnt it? and should facts always be expressed in the present tense?<br/><br/>pls help thanks!