I bought a shirt because it was not only good ______ but also reasonable in price.
A:of quality
B:in quality
C:of a quality
D:in a quality
在南北回归线附近,降水较多的是( )
已知{an}是等比数列,前n项和为Sn(n∈N*),且 1a1 ﹣ 1a2 = 2a3 ,S6=63.
将一张宽为4cm的矩形纸片折叠成如图所示图形,若AB=6cm,则AC的长度为____ .
下列判断正确的是( )