First, you should use BGMSET to define a number to your music. Then use BGMPAUSE and BGMCONT
Example:
BGMSET 128,"[CDEFG>CDEFG<]"
BGMPLAY 0,128 'Play the mml on track 0.
WAIT 120
BGMPAUSE 0 'Pause track 0
BGMPLAY 1,5 'Plays another music on a different track
WAIT 120
BGMCONT 0 'Resume track 0
1そうだね プレイ済み