But before the cargo ship's strange shipping route was explained, there were many conjectures about "China coveting Singapore's military secrets in the advanced armored vehicles".
2
该楼被改建成一个秘密军事设施处。
The building was turned into a secret military installation.
《柯林斯英汉双解大词典》
3
然而,从我们现在知道的——这个领域公开的秘密军事研究,很清楚,经验简单地就检验了很多类似的技术。
However, from what we know from now-public secret military research in this area, it's clear that many of these sorts of techniques are simply tested empirically.