sentence: As a result , many high school students may not concentrate during classes , or whilst studying , since they have many things going through their heads ( since they 've been studying a lot ) .
modified: As a result , many High School Students may not concentrate during classes , or whilst studying since they have many things on going through their heads ( since they 've been studying a lot ) .
transformation: ORTH, ORTH, ORTH, PUNCT, PREP