_______about the hero's love story, most teenagers are interested in the novel _______the Second World War.
A:Concerned, concerned
B:Concerning, concerning
C:Concerned, concerning
D:Concerning, concerned
请把下列生物与之相对应的生殖和发育特点搭配(只填序号)
A、青蛙 B、麻雀 C、蜜蜂 D、螳螂 E、月季
设复数zz∈C在映射f下的象是Z-·i,则-1+2i的原象为( )
蝗虫是比较常见的昆虫,它危害玉米、高粱和水稻等多种农作物,是有名的农业害虫。蝗虫的呼吸是靠 ( )