B-29: break the back of 攻破难关
A: How are you getting on with the essay?
A: 你的论文写得如何了？
B: I have broken the back of it. What I need to do now is to complete the conclusion and the typing of the paper.
B: 我已经完成了最难干的部分。剩下的就是一个总结，并把它打出来了。
A: I can type it for you.
A: 我可以为你打字。
B: You are so kind.
B：你真是太好啦。
