Now it appears that these predators have a third trick up their sleeves—or rather, wings—that allow them to be so silent but deadly.

而现在看上去似乎这种捕食者还有第三种独门工具使得它们的行动隐秘而且致命，那就是翅膀。

He's tougher than he looks-- silent, but deadly.

他比看上去要强壮 不作声 但致命。

Balloon Bombs The Japanese wanted to find a way to bomb America that would be silent but deadly.

5. 气球炸弹 日本人想找到一种无声但致命的轰炸美国的方法。