Be present (6)
I believe the answer is:
attend
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">be present</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for attend that I've seen before include "Wait and listen" , "Listen carefully" , "Watch" , "visit" , "Escort (someone)" .)