秘訣的英文：
the secret solution to a problem; the key; a knack; mystique

A secret between more than two is no secret
两人以上知道的秘密就不算秘密

I confide a secret to a friend.
我向朋友吐露了秘密。

The secret store is headquartered abroad.
这家黑店的总部设在国外。

It is an easy solution, but not the correct solution.
这是一个容易的方法，但不是正确的方法。

Relating to or designating a solution that contains one mole of solute per liter of solution.
摩尔的有关或指定一种溶液，其每升溶液包含有一摩尔溶质。

In some cases the solute can associate in solution.
在某些情况下，溶液中的溶质可以互相结合。

It was a complex problem.
这是一个复杂的问题。

Is the problem that easy?
问题有那么简单吗?

This is a prime problem.
这是一个有关质数的问题。