A:asinA=bsinB
B:acosA=bcosB
C:asinB=bsinA
D:acosB=bcosA
Many a student __________ wearing MP3 players while walking on the street. It's quite dangerous. ( )
选出正确的读音。
白霜(shuān shuāng)____ 思念(liàn niàn)____
北京是我国重要的政治、经济、文化中心.( )(判断对错)