Passé composé or imparfait: it is a decision, not a rule you look up

Every course teaches this the same way. Imparfait for description, habit and background; passé composé for completed actions. Then you write a real paragraph and the rule stops helping, because half the sentences could honestly take either one, and the textbook never said what to do about that.

The reason is that the rule is describing an effect rather than a cause. The tenses are not two boxes that facts fall into. They are two camera angles on the same event, and French makes you choose one every time you write a past-tense sentence. Once you see it that way, the cases that felt arbitrary stop being arbitrary.

What each tense actually does

Passé composé puts a boundary on the event. It says: this happened, it finished, and the story can now move on. Imparfait removes the boundary. It says: this was going on, and I am not telling you when it started or stopped, because that is not the point.

That is why the same action can take either tense. Il pleuvait and il a plu are both correct French about the same rain. The first makes the rain the setting for something else. The second makes the rain the event. Nothing about the weather decided that. You did.

This is the single most useful thing to internalise, because it turns an impossible memory task into a question you can actually answer while writing: am I setting a scene, or am I moving the story forward?

Where the trigger words let you down

You were probably given a list. Toujours, souvent, chaque jour take imparfait. Soudain, tout à coup, hier take passé composé. The list is a reasonable starting point and it is not a rule, and examiners see the difference immediately.

Chaque jour, il a pris le même train pendant trente ans is correct. The repetition is real, the marker word is right there, and the tense is passé composé, because the whole thirty years is being presented as one closed block. A candidate following the list would have written prenait and produced a different, also correct, sentence with a different meaning.

The lists fail because they are trying to predict your intention from your vocabulary. Nothing can do that.

The three patterns worth actually knowing

Interruption. A continuing situation in imparfait, cut across by an event in passé composé. Je dormais quand le téléphone a sonné. This is the pattern exam prompts invite most often, because narrative openings usually hand you a scene and expect you to disturb it.

Sequence. Several closed events, one after another, all in passé composé. Il est entré, a posé son sac, a ouvert la fenêtre. Slipping into imparfait here is the most common way a script loses its forward motion and starts to feel static.

Change of state. Verbs like savoir, vouloir, pouvoir and connaître shift meaning with the tense. Je savais is I knew, as a background fact. J'ai su is I found out, at a moment. This is not an exception to the boundary idea. It is the boundary idea applied to a verb whose meaning happens to sit on the boundary.

What this costs you in the exam

Section A of the TEF Canada expression écrite hands you the opening of a factual text and asks you to continue it. It is, in practice, a tense-consistency test wearing a narrative costume. The text you are given has already chosen its camera angle, and your continuation has to keep it.

Markers do not deduct once per wrong verb. What they see is whether a script holds a tense system together across a whole text, and that is very different from getting individual verbs right in isolated exercises. A candidate who is correct sentence by sentence but drifts between angles paragraph by paragraph reads as someone who has learned the forms and not the choice.

The same thing shows up in speaking, faster and more visibly. In the point-of-view task on the TCF Canada expression orale, the candidates who sound in control are the ones who set a scene in imparfait and then move through it in passé composé, without stopping to think about which is which.

How to practise it so it sticks

Stop doing gap-fill exercises. They give you the answer by giving you the context, which is precisely the part you have to supply yourself in the exam. What works better is writing the same short paragraph twice, once with the event in the foreground and once in the background, and seeing what changes.

Then have it read. This is the awkward part of the honest answer: tense drift is invisible to the person who wrote it, because to you the text reads exactly as you intended. It takes about three marked texts before most candidates can see their own pattern, and about ten before it stops happening. That is the argument for marked writing rather than more input.

If you want to know whether this is the ability holding your file back at all, run your last practice result through the score converter first. If your writing is already at your target band, the honest advice is to spend the time on whichever section is not.