一道单选must have been 和would have been的区别?
Jack described his father, who _______a brave boy many years ago, as a strong–willed man
A. would be B. would have been C. must be D. must have been
我不能理解为什么不能用would表示过去,他父亲过去是一个勇敢地男孩不行吗?
老师说would be可以说是过去的某个事。比如说：I would be a clever boy.之类的。