如图,半径为4的球O中有一内接圆柱,当圆柱的侧面积最大时,球的表面积与该圆柱的侧面积之差是____
—John didn't stop looking for a job _________ he got an offer from a German company.
—Lucky him. It's not easy for university graduates to get a good job now.
下列各组数中互为相反数的一组是( )