I would have written before, but I ______ill.

I would have written before, but I ______ill.
A、were
B、had been
C、would be
D、was
【正确答案】：D
【题目解析】：句中“I would have written before”用了虚拟语气，是对过去事实的假设，所以后面陈述的事实一定是过去的事实。