“费劲的”的英语可以翻译为：laborious，trying ...

不大可能叫你做什么太费劲的事儿。It's unlikely that you'll be asked to do anything too taxing.查阅他的客户名单是个相当费劲的活儿。Going through his list of customers is a massive job.爬到山顶上去是很费劲的.It was a stiff climb to the top of the hill....