By using MP3，a 600M-byte music CD can be (71) to 50M bytes or less．It can be streamed(downloaded in chunks)so that you can begin listening to the opening bars while the (72) ofthe life arrives in the background。And most important，MP3 music files retain good listening (73) that (74) compression schemes lacked．That (75) of features makes accessing anddistributing music on the Web practical for the first time．
A．amount
B．mass
C．quantity
D．quality
