—Have you finished your work ___________, Jane?
—Yes, I've done it ___________.
A:already; yet
B:yet, already
C:yet; yet
D:since, already
若2x-1x-3在实数范围内有意义,则x的取值范围是( )
下列哪种地图无法表示山峰或海底坡度的陡缓?( )
下图为初中化学几种常见物质及其转化关系,请根据图示回答