13. The negotiation proved to be successful.
谈判最后得到了成功。
还能这样说：
The negotiation was a big success.
The negotiation was rounded off.
应用解析：
prove of great value 证明很有价值；
prove up to the hilt 充分证明

14. No date has been set for further negotiations.
没有确定下次谈判日期。
还能这样说：
The date for further negotiations is not sure.
We haven't agreed on a fixed date for next negotiation.
应用解析：
go out of date 过时的，废弃的，不再流行的；
to date 迄今，到目前为止；
bear the date 注明日期；
keep a date 赴约；
date back to 自某时代至今

15. If you have any problems about the details, please let me know.
如果你对细节有任何疑问，请告知我。
还能这样说：
Are there any questions about the details? I'm always at your service.
Do you have any problems about the details? You can ask me.
应用解析：
let by 让……过去；
let off dissent 发泄不满；
let in for 使陷入，引起麻烦；
let us say 比如，例如；
let sb. into one's secret 让某人知道其秘密；
let sb. in the act 让某人参加此项行动

16. Nothing wrong will happen, so long as the quality of your article is good.
只要商品质量可靠，就不会有问题。
还能这样说：
Everyting will be OK if you can ensure the quality.
If the quality is good, everything will be OK.
应用解析：
before long 不久以后；
for long 很久；
at the longest 至多，最长；
go a long way 很成功；
go a long way towards sth. 对某事大有裨益；
happy as the day is long 非常快乐

17. We shall be able to better satisfy our customers quantitatively.
我们相信能在数量上更好地使客户满意。
还能这样说：
We can make our customers satisfied with quantity.
The quantity we offer can satisfy our customers.
应用解析：
be better than one's word 做的多于所许诺的；
a better part of 过半；
had better 最好，应该；
better oneself 自求上进，赚更多的钱