A:the residents would be permitted
B:had the residents been permitted
C:would the residents be permitted
D:the residents had been permitted
用化学用语填空:(1)三个氢原子____
(2)两个五氧化二氮分子____(3)3个氢氧根离子____
(4)氧化镁中镁元素为+2价____
构建模式图,探究地理基本原理、过程、成因及规律,是学习地理的方法之一.读图,完成下题.
将发芽率98%的种子平均分成甲、乙两组,甲组播种在肥沃的土壤中,乙组播种在贫瘠的土壤中,其他条件完全相同且适于种子萌发,则这两组种子的萌发情况是( )
_______ you have visited the Great Wall, you can't imagine how great it is.