What does it mean in the sentence - 取得成功的人往往都经历过许多失败，他们和普通人的区别就是他们都坚持了下来 ? I know that 下来 is the "it's going down", but i don't know what meaning it has here.
It means: They persisted and carried on. They did not give up.
If your question focuses on why "下来" is used here: It (as well as other "来/去" words) is frequently used in retrospect of past progress and completion. I am not sure if this is formal enough in official writing but it is common. Consider the next examples:
- 一路走来 / 一路走下来
- 这几个月下来 / 这几个月以来
- 坚持不下来 / 坚持不下去
These are all acceptable uses.
来 refers to the action of coming/walking over from a far point (start) to a near point (end), and 下 is the direction of counting from the start/top to the end/bottom; combined, 下来 means through the entire journey (from start/far to end/near).
- 取得成功的人往往都经历过许多失败，.... 他们都坚持了下来 - Oftentimes, the successful persons have had experienced quite a few failures (on the way to success), ... they all clung to the journey (from start to the end) regardless.