boundary

n.分界线，边界

bottom, bottom drawer (US hope chest), bottom line (infml 口), bottom-line, bottomless, bottommost, botulism, boudoir, bouffant, bougainvillaea, bough, bought, bouillon, boulder, boulevard, bounce, bouncer (also bumper), bouncing, bouncy, bound, bounded, bounden, bounder, boundless, boundlessly, bounds, bounteous, bounteously, bounteousness, bountiful, bountifully, bounty, bouquet, bouquet garni, bourbon, bourgeois, bourgeoisie, bourse, bout, boutique,