过去完成时的判断依据

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 o'clock 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，as soon as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 didn't. 3.根据上、下文来判定。

I met Wang Tao in the street yesterday. We hadn't seen each other since he went to Beijing.