Ever since Harry had come home for the summer holidays, Uncle Vernon had been treating him like a bomb that might go off at any moment, because Harry Potter wasn't a normal boy. As a matter of fact, he was as not normal as it is possible to be.
{Ever since|Since|From the moment} Harry had {come|returned|arrived} home for the summer {holidays|vacation|break}, Uncle Vernon had been treating him like a bomb that might {go off|explode|detonate} at any {moment|second|instant}, because Harry Potter wasn't a {normal|regular|ordinary} boy. {As a matter of fact|In fact|The truth was}, he was as {not normal|abnormal|unusual} as it {is|was} possible to be.