Поставьте данные существительные в множественное число. motto, toe, negro, berry, cliff, valley, belief, hero, carpet, play, wolf, photo, valley, manifesto, thief, match, mosquito, knife, piano, handkerchief, safe, tomato, potato, lady, box, wife, chief, loaf, grief, spy, swiss, hoof, memory. maid-servant, major-general, custom-house, man-of-war, 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.

Mottoes, toes, Negroes, berries, cliffs, valleys, beliefs, heroes, carpets, plays, wolves, photos, manifestoes, thieves, matches, mosquitoes, knives, pianos, handkerchiefs, safes, tomatoes, potatoes, ladies, boxes, wives, chiefs, loaves, griefs, spies, Swiss, hoofs(hooves), memories.

Maid-servants, major-generals, custom-houses, men-of-war, hotel-keepers, mothers-in-law, pocket-knives, schoolgirls, watchmakers, lookers-on, passers-by, fishermen, text-books, statesmen, editors-in -chief, sisters-in-law, bus-drivers, courts-martial, arm-chairs, men-servants, merry-go-rounds, room-mates, grown-ups, forget-me-nots.