gravity

n.地心引力，重力；庄重，严肃；严重

grating, gratingly, gratis, gratitude, gratuitous, gratuitously, gratuitousness, gratuity, grave, gravel, gravelly, gravely, graven, graven image, gravestone, graveyard, graving dock, gravitate, gravitation, gravitational, gravy, gravy train, gravy-boat, gray, grayscale, graze, grazier, grazing, grazing land, grease, grease-gun, grease-paint, grease-proof paper, greasily, greasiness, greasy, great, Great Britain, great circle, greatcoat,