查字典中考网整理了关于2020年中考英语知识点之过去完成时的判断依据，希望对同学们有所帮助，仅供参考。
1. 由时间状语来判定：一般说来，各种时态都有特定的时间状语。与过去完成时连用的时间状语有：
（ 1 ） by + 过去的时间点。
如： I had finished reading the novel by nine oclock last night.
（ 2 ） by the end of + 过去的时间点。
如： We had learned over two thousand English words by the end of last term.
（ 3 ） before + 过去的时间点。
如： They had planted six hundred trees before last Wednesday.
2. 由过去的过去来判定：过去完成时表示过去的过去，是指过去某一动作之前已经发生或完成的动作，即动作有先后关系，动作在前的用过去完成时，在后的用一般过去时。这种用法常出现在：
（ 1 ）宾语从句中
当宾语从句的主句为一般过去时，且从句的动作先于主句的动作时，从句要用过去完成时。在told, said, knew, heard, thought等动词后的宾语从句。如：
She said that she had seen the film before.
（ 2 ）状语从句中
在时间、条件、原因、方式等状语从句中，主、从句的动作发生有先后关系，动作在前的，要用过去完成时，动作在后的要用一般过去时。如：
When I got to the station, the train had already left.
After he had finished his homework, he went to bed.
注意： before, after 引导的时间状语从句中，由于 before 和 after 本身已表达了动作的先后关系，若主、从句表示的动作紧密相连，则主、从句都用一般过去时。如：
Where did you study before you came here?
After he closed the door, he left the classroom.
（ 3 ）表示意向的动词，如hope, wish, expect, think, intend, mean, suppose等，用过去完成时表示原本，未能
We had hoped that you would come, but you didnt.
3. 根据上、下文来判定。
I met Wang Tao in the street yesterday. We hadnt seen each other since he went to Beijing.