For #3 you could put La gente en el centro comercial nos entiende. (The people at the mall understand us.)
I don't know about #4 sorry.
But hopefully this helps
Answer:
Dominicana
Explana
the demonym in spanish are different according to the gender, female ends in A, and if it were plural AS
Answer:
16. eres
17. es
18. son
19. es
20. son
This are different ways to say "are " in spanish hope it help.
Explanation: