bulldog clip

clip with a spring that closes tightly and is used for holding papers, etc together （夹纸用的）弹簧夹.

building society, buildings, built, built-in (also in-built), built-up, bulb, bulbous, bulge, bulgy, bulk, bulk buying, bulk order, bulkhead, bulky, bull, bull's-eye, bull-headed, bull-necked, bull-terrier, bulldog, bulldoze, bulldozer, bullet, bullet-headed, bullet-proof, bulletin, bulletin board, bullfight, bullfighter, bullfighting, bullfinch, bullfrog, bullhorn, bullion, bullish, bullock, bullring, bullshit, bully, bully-boy,