你的句子可以改写成：
The key to success is to focus our conscious mind NOT on things we fear BUT on things we desire .——Brian Tracy
记住以下结构：A is B,not C == A is not C BUT B.
又如：
I have come to work not to visit == I have come not to visit but to work 你的句子可以改写成：
The key to success is to focus our conscious mind NOT on things we fear BUT on things we desire .——Brian Tracy
记住以下结构：A is B,not C == A is not C BUT B.
又如：
I have come to work not to visit == I have come not to visit but to work