一个月有28日至31日，“一个月的星期日”就意味着连续三十个星期。

另一种解释是：一星期有七天，“一个月的星期日”可能意味着四个星期。

总之，这个成语喻指“很长的时间”。

例：He could easily have revenged himself by giving me a kick with heavy shoes on the head or the loins that would have spoiled my running for a month of Sundays.

（他若要报仇，那很容易，只要用其沉重的靴尖向我头部或腰部一踢，就可使我长时间不能行走。）

　　A: How about this work? 这个工作怎样？

　　B: I think it will take me a month of Sundays to finish. 我想得花很长时间才能完成它。

　　A: You will have a long time to be very busy, right? 你又会忙一段时间了，是吗？

　　B: Yeah. To be very tired, too. 就是，也会很累。

　　A: In some way, it is good for us because we can learn lots of things from it. 在某种程度上，这对我们有好处，因为我们能从中学到很多东西。