back and forth

来回，来往

baby grand, baby tooth, baby-faced, baby-minder, baby-sit, baby-sitter, baby-sitting, baby-snatcher, baby-talk, babyhood, babyish, Babylonian, baccalaureate, baccarat, bacchanal, baccy, Bach, bachelor, bacillus, back, back away, back down, back down off, back down/off, back number, back of, back out of, back road, back room, back seat, back talk, back up, back-bench, back-bencher, back-breaking, back-formation, back-pedal, back-up, back-yard, backache,