A:that
B:where
C:which
D:whe
读我国四个省级行政区轮廓图,回答以下问题。
在Rt△ABC中,∠C=90°,AC=3,AB=5,则它的内切圆与外接圆半径分别为( )
Security devices at airports are ______ to spot weapons that could be used by terrorists.
设定义在R上的奇函数y=f(x),满足对任意t∈R都有f(t)=f(1﹣t),且x∈0,12时,f(x)=﹣x2,则f(2015)的值等于( )