Were it not for your help,I wound never be a good teacher.

虚拟式were也可以表示与过去事实相反的假设,如：
If I were not busy,I would have come.
希望我能帮助你解疑释惑.还有一个疑问就是Without his help,we would not have made such rapid progress.主句表示与现在事实相反，从句表示与过去事实相反，属于混合时间虚拟语气，所以我觉得应该改成we would not make such rapid progress.不知道我的想法对不对如果是含蓄条件（无if从句），可根据实际情况选择与现在或过去事实相反的虚拟语气，不是混合时间虚拟语气。希望我能帮助你解疑释惑。