@Yulin,
Yulin wrote:
Which one is not weird the most?
1) not only the world's first but also the best
2) not only the first but also the best in the world
or other more suitable sentence? (I would like to emphasize we are both FIRST and BEST .
I find 2 better in terms of usual and easily understandable constructions.
An alternative might be: "the first, and still the best, (whatever)"
It had to be the "best" when it was the first, because it was the ONLY one (in that sense it was also the worst, because there was nothing to compare it to). Generally, with time, attempts are made to improve on an innovation--that's why I suggest the word "still."