最费劲 meaning in Chinese

the most trying

Give me the worst first
“先给我最费劲的。 ”
They always make their pens out of the hardest , toughest , troublesomest piece of old brass candlestick or something like that they can get their hands on ; and it takes them weeks and weeks and months and months to file it out , too , because they ve got to do it by rubbing it on the wall
他们总是用最坚硬最结实最费劲的东西，象旧烛台啊，或是能弄到手的别的什么东西，用来做成笔。这就得花好多个星期好多个月才能锉成笔，因为他们非得在墙上锉。