The location of the ship is a closely guarded secret.

那艘船的方位是高度机密。

These days, the Coca-Cola recipe is a closely guarded secret.

如今，可口可乐的配方是一个严格保守的秘密。

In the past, information about orbits was a closely guarded secret.

在过去，关于轨道的信息是严格警戒的秘密。

The tower's height has been kept a closely guarded secret until now.

直至今日，迪拜塔的“身高”仍是个秘密。

The roaster's blending knowledge is usually a closely guarded secret.

烘焙高手混合咖啡豆的知识可谓是最高的行业机密。