The past perfect tense is best understood if it is called the " before" tense.When we wish to indicate that an event happened before another event in the past, we use the past perfect, it means to order the events in the past.
We use the past perfect to talk about something occurred before another action in the past
-The lesson had begun when we arrived .
Here in this sentence :two actions in the past :
1- The begining of the lesson
2- Our arrival
The first action "1" is in the past perfect ,and the second action "2" is in the simple past tense.
The simple past can be used instead of the past perfect when before or after is used in the sentence.The words before and after actually tell you what happens first so the past perfect is optional .Look below, both sentences are correct:
- When we got the station,the train had left.
- The train left before we arrived .
The word before makes the order quite clear and the past perfect is unnecessary.
We form the past perfect with had + the third form of the verb "past participle "
- We hadn't thought about the consequences."negative"
- Had you already met him? "question"
Let's review the three tenses of the past in this exercise :
Change the infinitive in brackets to the past perfect ,simple past or past continuous:
1-He ( forget ) my name ,so I reminded him.
2-My teacher ( give ) me a good report last term.
3-While we ( walking ) out ,it started to rain.
4-The film ( start) when we arrived.
5- When he ( get) home the children were playing in the garden .
6-He was working there when the war ( break ) out.
7-He already ( finish ) his study ,when he came back home from London.
8- The fire had already destroyed much of the building when the firemen( arrive).
Thank you for reading