I'm not sure what you are talking about exactly, but I would think thats false.
Answer: 1-Los chicos son simpáticos.
2- La ciudad es única
3- Los monumentos son antiguos
4- La plaza es agradable
5- El tráfico es horrible
Explanation: "La" is for singular
words that end with a. "Él" is for singular words that end with o. "Es" is for singular and "son" is for plural
What situation are you referring to?
The first one is conoce
the second one is sabe
and the third one is conoce
and im super sure this is correct because im spanish