he speaks Chinese as fluently as if he __a Chinese A were B had been C is D has been 求详解,

题目

he speaks Chinese as fluently as if he __a Chinese A were B had been C is D has been 求详解,

答案

A were
这里要用虚拟语气,表示“仿佛他是个中国人”而他实际不是——与现在事实相反
as if 从句用陈述语气的情况：当说话者认为句子所述的是真实的或极有可能发生或存在的事实时.　　如：　　It sounds as if it is raining． 　　听起来像是在下雨.
as if 从句用虚拟语气的情况：当说话人认为句子所述的是不真实的或极少有可能发生或存在的情况时.从句虚拟语气动词时态的形式如下：　　（1）如果从句表示与现在事实相反,谓语动词用一般过去时.　　如：　　You look as if you didn’ t care． 　　你看上去好像并不在乎.
（2）从句表示与过去事实相反,谓语动词用“had+过去分词”.　　如：　　He talks about Rome as if he had been there before． 　　他说起罗马来好像他以前去过罗马似的.
（3）从句表示与将来事实相反,谓语动词用“would/could/might+动词原形”.　　如：　　He opened his mouth as if he would say something． 　　他张开嘴好像要说什么.
as if 后面可以接陈述语气和虚拟语气,如果句子的情况是真实的,那么只要保持时态一致即可,如果后面接的并非真实情况,则要按照虚拟语气规则把句子形式改变（简单说就是时态倒退原则）.