alsamixer telles me Master and PCM is always 0, why

[Trace Green]

Hello, I think my sound card is driven sucessfully, because when i start 
up teamspeak, it telles me sound card workes well, but, i can not hear 
any voice, so , i use alsamixer to check, but i find Master and Pcm item 
is just 0, i can not up or down sound , so , i guess this is the 
problem, Does anyone  meet this problem? How shall i fix it?