A comment on the whole sentence
An adverbe de phrase (sentence adverb) doesn't describe how something happens but how you stand towards the statement. It is also called a modalisateur, because it grades the statement: certain, likely, possible, obvious. The sentence stays the same; only your stance changes.
Il a oublié la réunion.
He forgot the meeting.
A plain statement.
Il a visiblement oublié la réunion.
He has obviously forgotten the meeting.
You can see it; he isn't there.
Il a sans doute oublié la réunion.
He has probably forgotten the meeting.
A guess.
The scale of certainty
Two words are weaker than they look. sans doute means 'probably', not 'without doubt'. certainement in everyday speech usually means 'most likely'. You are really certain only with sans aucun doute or the more formal assurément.
From possible to certain
| Certainty | Adverb | Example |
|---|---|---|
| possible | peut-être | Elle viendra peut-être. |
| likely | probablement, sans doute | Elle viendra sans doute. |
| very likely | certainement | Elle viendra certainement. |
| certain | sans aucun doute, assurément | Elle viendra sans aucun doute. |
How you know
Three adverbs say what your judgement rests on. apparemment rests on appearances or on what you've heard, and often carries a hint of doubt. visiblement rests on what you can see right now. manifestement says it's plain to everyone and sounds a little more formal.
Apparemment, le restaurant a changé de propriétaire.
Apparently the restaurant has changed owners.
Something you've heard.
Tu es visiblement épuisé, rentre chez toi.
You're visibly exhausted, go home.
Le rapport a manifestement été écrit à la hâte.
The report was clearly written in a hurry.
Certes, le projet est coûteux, mais il est nécessaire.
Admittedly, the project is expensive, but it is necessary.
certes concedes a point before mais pushes back.
Where the adverb goes
Sentence adverbs go at the start with a comma, or straight after the conjugated verb. With peut-être and sans doute at the start you have a choice: in speech you add que, in formal writing you invert subject and verb.
peut-être at the start
Spoken
Peut-être qu'il viendra ce soir.
Maybe he'll come tonight.
Sans doute qu'elle a raison.
She's probably right.
Written, formal
Peut-être viendra-t-il ce soir.
Perhaps he will come this evening.
Sans doute a-t-elle raison.
She is doubtless right.
