<!<del>StartFragment&gt;<br/><br/>I wonder if there is any difference grammatically between "that(1)" and "that(2)".<br/><br/>1. I can't believe that he's only 17.<br/><br/>2. What was that you were trying to say?<br/><br/>I think "3" is correct, I wonder if "4" is correct.<br/><br/>3. I can't believe that he's only 17.= I can't believe he's only 17.<br/><br/>4. What was that you were trying to say? = What was you were trying to say?