French language Q&A Forum

I got it wrong for using ces sont instead of ce sont. Kwiz pointed me to this lesson but it doesn't explain why ces is wrong.

One of the microkwiz questions I had on this lesson asked you to fill in the blank when talking about "my"... "Mes vêtements...." 

.. But the possessive is not covered in this lesson and ive not seen it mentioned so far in what I've studied on lawless. I've been googling for a while now but still confused as to how to conjugate for my/your/their 

Thanks

When looking around on the internet, it seems like "Retourner" is used here and there, both informal on message boards and formal on shopping sites (for example H&M website: "POUR RETOURNER UN ACHAT EN LIGNE"), for indicating returning an item.

Could you elaborate on this and why you write "Retourner never means to return (something) in the context of a shop for example." ?

I thought with occupations there was no article prior to the occupation. Je suis médecin, not je suis un medecin. Is this an exception?

For: La police est arrivée trop tard.

In english, police and policemen are (la même chose) the same thing, plural nouns, yes? So why then is 'The police arrived too late.' a correct answer and 'The policemen arrived too late.' is not?