Grammar fix, bug 4526

lang/en_utf8/quiz.php

@@ -183,7 +183,7 @@
 $string['gradingdetailsadjustment'] = 'With previous penalties this gives <strong>$a->cur/$a->max</strong>. ';
 $string['gradingdetailspenalty'] = 'This submission attracted a penalty of $a. ';
 $string['gradingdetailszeropenalty'] = 'You were not penalized for this submission. ';
-$string['guestsno'] = 'Sorry, guests can not see or attempt quizzes';
+$string['guestsno'] = 'Sorry, guests cannot see or attempt quizzes';
 $string['hotpot'] = 'Hot Potatoes format';
 $string['illegalformulasyntax'] = 'Illegal formula syntax starting with \'$a\'';
 $string['imagedisplay'] = 'Image to display';