birch

n.桦树，白桦

biographer, biographic, -ical, biography, biological, biological control, biological warfare (also germ warfare), biologically, biologist, biology, biomedical, bionic, bionics, biopsy, biorhythm, bioscope, biotechnology, bipartisan, bipartite, biped, biplane, 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 rate,