In French 3, level 18, the phrase “appelle une ambulance” is translated as “call an ambulance” - why is the 2nd person singular not used here - “appelles une ambulance” or the 2nd person plural “appellez une ambulance”?
In the absence of the a subject for these, I’d be inclined to translate the first one as “[he/she] calls an ambulance”.
because it is the imperative mode: (2nd person sg) appelle; (let us call…) appelons; (polite or plural) appelez
(no grammar book/site available there? 
)
First group verb (ends -er) at the imperative has no “s” at 2nd person, except when you use them with certain expressions where a vowels comes next ie : “en” ou "y"
parles-en, retournes-y …
thank you.
Memrise could take a page from Duolingo’s book and put a grammar note on the solution page. In my opinion that would be worlds more useful than the meme stuff.
you’re welcome! (btw, and sorry for, but it is “mem/mems” and not “meme”)
Oui faut laisser mémé tranquille.
It is an option for course creators to add mems to explain certain aspects of grammar. But you can also add it on yourself, this way you help others too. Consider Memrise more like a flashcard system.
Duolingo is a lesson course. They are complementary.