1.This is the day <b>that</b> he left <b>on</b>.<br/><br/>-&gt; This is the day <b>that</b> he left.<br/>-&gt; This is the day he left <b>on</b>.<br/>-&gt; This is the day <b>when</b> he left<br/><br/>Can I write the three sentences for the same meaning of the #1 sentence?<br/><br/>Or is the sentence correct or should it be 'This is the day <b>which</b> he left <b>on</b>.'?<br/><br/>What do you native English speakers think?<br/><br/>Thank you so much as usual in advance.