Что означает сокращение "rb"???​

Зависит от контекста

в сочетании BRB - be right back

может reconnaissance bomber - самолет-разведчик

еще rb - regular budget ( редко)

Объяснение:

you mustn't open the door for a stranger. a stranger should trick you. you might answer the phone. you don't have to tell everybody that you are home alone . you must know your parents' phone number. it have to be wise to know your neighbours .

whether the brother now reads the book, whether he plays the computer, whether the grandmother sleeps, whether mum prepares a lunch, whether the grandfather the tv looks, whether the father reads, whether kate plays the piano, whether the brother listens to music, whether reks near to it sits.