By using MP3, a 600M-byte music CD can be (70) to 50M bytes or less. It can be streamed (downloaded in chunks)so that you can begin listening to the opening bars while the (71) of the file arrives in the background. And, most important, MP3 music files retain good listening (72) that (73) compression schemes lacked. That (74) of features makes accessing and distributing music on the Web practical for the first time.

A．pressed

B．compressed

C．press

D．compress

地图投影就是依据一定的数学法则，将不可展开的地表曲面映射到平面上或可展开成平面的曲面上，最终在地表面点和平面点之间建立一一对应的关系。