birth rate

ratio of births in one year to every thousand people 出生率.

birch, bird, bird of paradise, bird of passage, bird of prey, bird sanctuary, bird-bath, bird-song, bird-table, bird-watcher, birdbrained, birdcage wire, birdie, birdlime (also lime), birds, birdseed, biretta, Birmingham, birth, birth certificate, birth-control, birthday, birthmark, birthplace, birthrate, birthright, biscuit, bisexual, bisexuality, bishop, bishopric, bismuth, bison, bistro, bit, bit by bit, bit part, bitch, bitchiness, bitchy,