哦，知道了，那么以“”开头的比较正式，象调查。

Oh ok, I see , so the one with an "I" is actually more formal, like an investigation.

youdao

看起来好象警察已经认输了，并且要放弃调查。

It seemed as if the police had thrown in the towel and were abandoning the investigation.

《柯林斯英汉双解大词典》

象他这样一个得到机会和特许来从事这种探索，而且又有熟巧将其进行下去的调查人，很少有秘密能逃过他的眼睛。

Few secrets can escape an investigator, who has opportunity and license to undertake such a quest, and skill to follow it up.

youdao