Do you see the bird ________ beautiful feathers? It is singing ________ a tree.
A:with; in
B:with; on
C:to; in
“故有无相生,难易相成,长短相形,高下相倾,音声相和,前后相随。”从思想内容和表达形式看,此话出自( )
下列关于物质的物理属性及应用的说法,正确的是( )