【正确答案】 D

【答案解析】该题是语法结构题，考查虚拟语气在含蓄条件中的用法。 在此用法中，条件不是用一个条件句来表示，而是隐含在诸如without、but for、but that等引导的短语或句子中，或由连词but、副词otherwise以及比较等级等表示的上下文中，如：But that she was afraid, she would have gone there alone. 要不是害怕，她就独自一人去了。又如：A more careful person wouldn't have made so many mistakes. (=If you had been more careful, you wouldn't have made so many mistakes.)如果细心一点，就不会出这么多错误了。因此，选项D为最佳答案。