John promise his wife he_not smoke and he has never smoked ever since为什么要用would
问题描述：
John promise his wife he_not smoke and he has never smoked ever since为什么要用would
答
该宾语从句前半部分使用虚拟语气情形,与说话时的现实情况相反；后半部门讲的是自那以后发生持续到现在的真实情况,所以用现在完成时