Question

Nous___un sandwich en ville( manger)

Answer 1

Hi !


Nous mangeons un sandwich en ville

Manger (infinitive)

you have to add a "e" before "o" to have the sound as "jo/in' otherwise you'll have a sound as "go"
je mange
tu manges
il/elle/on  mange
nous mangeons
vous mangez 
ils/elles mangent

same when you'll have to conjugate at the "imparfait"
je mangeais
tu mangeais
il mangeait
nous mangions
vous mangiez
ils mangeaient

so before the vowels "a" and "o" , you have to add an "e" to get the sound  "je" as "join'...otherwise you get an improper sound as "go"

Not sure my explanations are very understandable, but I tried !!!

have a nice day !!

Answer 2

Hi, it would be "Nous mangeons un sandwich en ville" 

Manger- which means to eat
Je- mange      nous mangeons
Tu- manges    vous mangez 
il/elle- mange  ils/elles mangent

hope i helped!