这就是制作好番茄酱的秘诀。

That's ___the ___secret to making a good tomato sauce.

那么你成功的秘诀是什么？

So what's ___the ___secret of your success?

这种饮食的秘诀是你必须非常乐观。

___The ___secret of this diet is that you have to be very optimistic.