tricky

tricky [ˈtrɪki]

adj. 狡猾的; 微妙的; （形势、工作等） 复杂的; 机警的

This is a tricky one to answer. 这是个难以回答的问题。

It's a devil of a tricky problem. 这是个非常棘手的问题

It's a bit trickier than we thought. 这比我们之前想象的更棘手。

be a bit trickier to do 干什么比较棘手
a bit trickier 棘手，困难

<1>   a bit tricky：有点棘手；有点诡异；
实际上是这样的结构：a bit (有点) + tricky(需要技巧、智谋的)
看几个例句：
1) This part is a bit tricky to understand.
   这部分有点难理解。
2) Starting from Thursday, I couldnt really say much from the results because 1st practice sessions are always a bit tricky.
   周四开始，我就觉得没什么太多的意见好发表，因为第一次的自由练习总是充满玄机。
3) The notation is actually there to make it easier, but (like programming-language syntax) notation is always a bit tricky and daunting on first contact.
   那些数学符号现在变得容易相处了，但（像编程语言的语法）一开始的话多少还是有点让人感到有些怪异。
<2>  tricky bit 棘手的问题，复杂的问题
这个是名词性短语
如下面的例句：
1) Getting there is the tricky bit but it is something we are all aiming for.
   夺取冠军是有点难，不过这亦是我们所有人的目标。
2)The tricky bit can be when we find that clarity (about what we need to do) and it scares the crap out of us.
  然而复杂的一点就是当我们明确了（我们需要做什么）的时候，我们又把自己吓倒了。
3) The tricky bit for Mr Brown as prime minister will be to find some way of differentiating himself from his predecessor.
  布朗当首相，如果够聪明的话，就是寻找一些能够彰显其与众不同的方式，与此来与其前任相区别