Поставьте следующие группы слов: а) во множественное число: our large city, my little sister, their large family, your best friend, this green street, our large lab, my happy day, that good flat, a green pencil, a good pen. б) в единственное число: those difficult texts, my best friends, their wives, our children, these long knives, our labs, good cities, these streets, these stops, their large flats, those dark horses, my feet, his teeth, big tables.
б) a difficult text, my best friend, my wife, my child, a good city, a stop, my large flat, a big table
Остальные, что не написала, я не знаю