Try very hard (4,1,3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">try very hard</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for bust a gut that I've seen before include "Really work extra hard" , "meet qualification for intestinal surgery?" , "Make a strenuous effort" , "Strain" , "Work extra hard to achieve something" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">try very hard</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for strive that I've seen before include "Make effort using rivets" , "Try extremely hard" , "Try hard to break rivets" , "Make a great effort" , "Vie; compete" .)