《老人与海》里有这么一段：
I can do nothing with him and he can do nothing with me, he thought. Not as long as he keeps this up.
这里我对第二句话句首的not的使用方法感到很疑惑。还请各位老师解惑。
我读到这里的时候感觉这两句完全可以写成一句话：
I can do nothing with him and he can do nothing with me, he thought, as long as he keeps this up.
这里我将he thought理解为主句，I can......with me理解为宾语从句提前，as long as ...up.状语从句。
不了解如此的理解是不是正确？
你的改动语法上是对的，意思也是对的，但风格变了，变得不那样像“小说”了。
句中的 Not as long as he keeps this up 可理解为省略使用方法，等于 I cant do anything with him as long as he keeps this up / Neither of us can do anything with eachother as long as he keeps this up的省略。
句子意思是：他心里想，我拿他无法，他也拿我没方法。只须他如此坚持着（指咬着钩线），我就拿他一点方法也没 / 大家两个就大家都拿他们无法。