m1 m2 m1 m2
m1 m2 m1 m2
v co v co
m1 m2 m1 m2 .
m̩˥ WORD_BOUNDARY m̩˧˥ WORD_BOUNDARY m̩˥ WORD_BOUNDARY m̩˧˥ WORD_BOUNDARY
m 1 WORD_BOUNDARY m 2 WORD_BOUNDARY m 1 WORD_BOUNDARY m 2 WORD_BOUNDARY . WORD_BOUNDARY