My mother and father has /have a big bedroom
My brother has/have a bike
в каких ситуациях WAS в каких случаях WERE ​

My mother and father have a big bedroom.

My brother has a bike.

I, he, she it → was

They, we, you → were

My mother and father have........

My brother has..........

I,he,she,it-was

You,we,they-were

Was-был,была ,когда подлежащее в един.числе

Were-были,когда подлежащее во множ.числе