b for 咩 先
b for me1 sin1
n:let L2 wh sfp
b for 咩 先 ?
 WORD_BOUNDARY  WORD_BOUNDARY m ɛ˥ WORD_BOUNDARY s i˥ n WORD_BOUNDARY
b WORD_BOUNDARY f o r WORD_BOUNDARY 咩 WORD_BOUNDARY 先 WORD_BOUNDARY ? WORD_BOUNDARY