Нужно поставить слова в множественное число maid- servant, major - general, custom-house, man - ofwar, hotel - keeper, mother - in - law, pocket - knife, schoolgirl, watchmaker, looker - on, passer - by, fisherman, text - book, statesman, editor - in - chief, sister - in - law, bus - driver, court - martial, arm - chair, man - servant, merry - go - round, room - mate, grown - up, forget - me - not.

maid-servants, major-generasl, custom-houses, men-of-war, hotel-keepers, mother-in-laws, pocket-knives, schoolgirls, watchmakers, lookers-on, passers-by, fishermen, text-books, statesmen, editor-in-chiefs, sister-in-laws, bus-drivers, court-martials, arm-chairs, man-servants, merry-go-rounds, room-mates, grown-ups, forget-me-nots.