下面几个英语句子什么意思?

下面几个英语句子什么意思?
I mean you can't keep disagreeing with your line manager over quite basic matters.it's just not on.there was too much conflict.其中的“it's just not on”
Many young members of middle managemament are seconded into HR for a year because their firms feel they can identify with job_seeking graduates.  其中的“second into”