You need to accord the participle when the past tense is formed with être. There are some other cases when it needs to match, like when you use avoir and the COD comes in front of the participle.

Yes, exactly. Otherwise it would be Vous vous êtes rasés ce matin? (unless you are talking to a group of ladies shaving their legs, of course, in which case it would be ....rasées...)

Vous vous êtes rasé ce matin? -- Did you shave this morning (using formal you, talking to a single person)

In this case "vous" is singular, referring to "you" as an individual, as apposed the plural "you's guys" :))

It's been a while. Does no one know the answer?

It's because there is a direct object "les dents". This question has been asked a lot, but so far the lessons have not been updated to explain this. Look at the answer to Gabrielle's question at the end of the Q&A here:

Agreeing past participle with subject's gender and number with (+ être) verbs in Le Passé Composé

Thanks so much for pointing me to the answer, Alan. I understand now but it's getting complicated! :) It would surely help if they'd add a note about it to both those lessons. I did read through all the questions on the lesson I asked about and didn't see an answer there. It should really be part of the lesson, or have a link to a lesson discussing it.

Hi Pauline,

"Vous" can be either singular or plural. In this respect it is very much like the English "you". If you use "vous" as a polite form of the 2nd person singular you must also match anything that depends on it to be in singular as well. The same goes for "vous" in the 2nd person plural.

Vous vous êtes bien amusé? -- Did you enjoy yourself? (addressed at one person).
Vous vous êtes bien amusés? -- Did you enjoy yourselves? (addressed to a group).
Vous vous êtes bien amusées? -- Did you enjoy yourseves? (addressed to an all female group).

Note that even in English you would use "yourself" if "you" stood for a single person and "yourselves" in case of a group of persons. Not so much different than French, eh?

-- Chris (not a native speaker).

Nous nous sommes brossés. Or alternatively, for an all female group: Nous nous sommes brossées  

-- Chris (not a native speaker). 

Nous nous sommes brossés. Or alternatively, for an all female group: Nous nous sommes brossées  

-- Chris (not a native speaker). 

Hi Deborah.  This caught me out too.  But I think the Kwiz answer (full answer: "Nous nous sommes brossé les cheveux") is correct.  According to e.g. http://la-conjugaison.nouvelobs.com/regles/orthographe/l-accord-du-participe-passe-des-verbes-pronominaux-188.php there is no agreement of the past participle with the subject when a direct object follows.  They give the example of "Ils se sont lavé les mains".  This would seem to apply here also.

Perhaps there is a lesson on this that I haven't found.  If not, it would be nice to have one.

ps. I read a recent article where it said that French school kids spend 80 hours on average learning the rules for past participle agreement!

Hi Paul,

I believe you are confusing the verb with the past participle. Let's take a look:

Alice s'est bien amusée. -- Alice had a lot of fun.

The verb is "est", which is the third person singular and hence agrees with Alice, the subject. The verb always needs to agree with the subject of the sentence, no matter what.

The participle in the example is "amusée". In the case of composite tenses which have être as their conjugated verb (as in this example), the participle needs to match the verb in number (singular) and gender (female), therfore you use "amusée".

Jean et Marc, vous vous êtes bien amusés?

Another example of the same kind: Jean et Marc are the subject in the second person plural and hence referred to as "vous". The verb (êtes) is matched to it. In the particular case of passeé composé with être as the conjugated verb, the participle needs to match the subject in gender and number: amusés. Another example, this time with avoir instead of être as the conjugated verb.

J'ai mangé du pain. -- I ate some bread.

Again, the verb "ai" is matched to the subject "je". The past participle "mangé", however, is not matched because the conjugated verb is avoir and not être.

With this clarification you should be able to reconcile the two explanations.

-- Chris (not a native speaker).

Hi Paul,

can you point to the contradiction you found, specificially? It would help me answer your question.

-- Chris.

Hi Mary,

conversational past is the tense you use in conversations when talking about some event that happened in the past.
This is to be contrastet to passé simple which fulfills this function but not on a conversational level but on a literary level.
The imparfait tense is different because it serves a different purpose and pertains to repeated or habitual actions in the past.

-- Chris (not a native speaker).