Weknowthattreesar的精選

問題詳情：完形填空，從每小題A、B、C、D四個選項中，選擇能填入相應空白處的最佳*。Weknowthattreesareusefulinoureverydaylife.They  1 usmanythings,suchaswood,oxygen(氧氣),rubber(橡膠),medicinesandmanyotherthi...