一个长难句,Work is therefore desirable ,first and foremost,as a p

一个长难句,Work is therefore desirable ,first and foremost,as a preventive of boredom,for the boredom that a man feels when he is doing necessary though uninteresting work is as nothing in comparison with the boredom that he feels when he has nothing to do with his days.as a preventive of boredom为啥加个as,还有后面as nothing in comparison with.