上班:
to go to work; to report for duty; to be at work; to be on duty; to be on the job
下班:
to get off duty; to come off work; to go off duty; to be released from duty
注意：如果你强调在班上,或者不在上班的状态可以用
be on/off duty
当你把上班当成动词,理解为去上班,去下班时,用
go to work; go on duty
come off work;come off duty