Tell what happened before something else

In A2 you told stories about the past with two tenses: the Past Simple — what happened (A2 #1), and the Past Continuous — what was going on at that moment (A2 #2). This is enough while the events come in order. But a story often takes a step back: "I got to the station — and the train had already gone." For this step English has a separate tense — the Past Perfect, the past before the past.

The form: had + the third form of the verb — the same form as in the Present Perfect (A2 #3). had is the same for all persons; there are no endings.

The short form 'd can also come from would — you know it from I'd like (A2 #17). It is easy to tell them apart by the next word: after had comes the third form (I'd finished), after would the base form (I'd like). For the verb have itself, the Past Perfect looks like had had: We had had dinner, so we weren't hungry. This is not a typo: the first had is the helping verb, the second is the third form of have.

Negatives and questions. The negative is hadn't + the third form, with no did at all: I hadn't seen him for years. A question is made as in the Present Perfect, only with had in place of have: Had you eaten? With a question word, had comes straight after it: Why had she left so early? Where had they gone? In a short answer the third form is not repeated: Yes, I had, No, she hadn't.

When it is used. The Past Perfect always looks back from some moment in the past. This moment — let us call it the point of the story — usually stands next to it in the Past Simple.

The first case — one event happened before another: When I got to the station, the train had left. First the train left, then I arrived.

The second — the reason for what came later: She couldn't get in because she had lost her keys. The keys were lost earlier, so the door did not open.

The third — experience up to a moment in the past: I had never seen the sea before that summer. This is the same as the Present Perfect for experience (A2 #4), only the counting starts not from "now" but from "that summer".

From this comes a short rule: the Present Perfect links the past with the present; the Past Perfect links an earlier past with a later one.

Compare. One form changes the order of events:

If the events are told in the order they happened, you do not need the Past Perfect: I got up, had a shower and left the house. The order is clear anyway. The past before the past is needed where the story goes back.

already, just, never, ever, yet. They go in the same place as in the Present Perfect (A2 #3, A2 #4): between had and the third form, and yet at the end of the sentence.

before is often added at the end of a sentence with never and ever: it reminds the listener that the counting starts not from today but from a moment in the past.

"For the first time": It was the first time… After this phrase you use the Past Perfect: It was the first time I had flown. — that was my first flight. The same after a superlative with ever: It was the best meal I had ever eaten. Many languages use an ordinary past tense here, but English counts the experience up to that moment — hence the past before the past. In the present the pattern is the same, but with the Present Perfect: It's the first time I've been here. In conversation you can also hear It was the first time I flew, but the Past Perfect is the norm.

More examples:

Don't say this. ✗ Did you had seen it before? → ✓ Had you seen it before? had makes the question itself, and did is not needed here.

Check yourself. Which event came first: When we got home, the guests had left? Which is had and which is would: I'd finished, I'd like? How do you say that, back then, you saw the sea for the first time?