Classroom trial (4)
I believe the answer is:
exam
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">classroom trial</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for exam that I've seen before include "School test (colloq.)" , "Something to sit" , "Important test" , "paper" , "Test (abbr)" .)