Поставьте множ. число boy, toy, day, spy, tree, book, thief, half, snowman, pilot, roof, cliff, mouse, child, tooth, fly, bus, bush, gnome, stone, rose, kilo, video, audio, mosquito.

Boys, toys, days, spies, trees, books, thieves, halves, snowmen, pilots, roofs, cliffs, mice, children, teeth, flies, busses, bushes, gnomes, stones, roses, kilos, videos, audios, mosquitoes.