已知X+、Y2+、Z—、W2—四种离子均具有相同的电子层结构。下列关于X、Y、Z、W四种元素的描述,不正确的是 ( ) A.原子序数:Y>X>Z>W B.离子半径:X>Y>Z>W C.原子最外层电子数:Z>W>Y>X D.还原性:X>Y,W2—>Z—2.---I think not only English but also maths __________ important.---Yes,that's why we should learn _________ of them well.( )A.are; bothB.are; eitherC.is,bothD.is; either