1. The solution to the problem was unobvious, but with careful analysis, it became clear.
问题的解决方法并不明显，但通过仔细分析，问题变得清晰了。
2. The unobvious connection between the two events was only revealed after conducting extensive research.
通过进行广泛的研究，这两个事件之间不明显的联系才得以揭示。