过去将来完成进行时的结构

过去将来完成进行时（Past Future Perfect Continuous Tense）是一种较为复杂的时态，用于描述一个动作从过去某一时间开始，一直延续到过去将来的某个时间点。这个时态在英语中并不常用，但在某些情况下可以非常有用，尤其是在转述或间接引语中。

结构

过去将来完成进行时的结构是：

should/would have been + 现在分词

例如：

1. She told me that by the end of the year she would have been living there for thirty years.

2. I knew by that time he would have been working there for 30 years.

3. She told me she’d have been teaching in that university for 20 years by that summer.

例子

肯定句

By the end of this year, I will have completed my degree.

否定句

She said that by the end of the spring term, she would not have been studying English for three years.

疑问句

Would you have been able to finish the project by Monday？

注意事项

过去将来完成进行时并不是一个常用的时态，所以在书面语和口语中，使用相对较少。

这个时态主要用于转述方面，即用于间接引语中。

在使用过去将来完成进行时之前，通常需要明确动作的起始时间和结束时间，并且动作是否继续下去需要根据上下文来判断。

希望这些信息对你有所帮助。