采用中心柱倒装法组装立式储罐，当公称容积小于300米3时采用（）中心柱，公称容积在400～500米3时采用（）中心柱。
参考答案：φ159×6；φ219×6
___________to be the greatest writer of plays in the English-speaking world, Williams Shakespeare is more famous than he was in his own lifetime.
A．Considered
B．To be considered
C．Having considered
D．Considering
同周期的X，Y，Z3种元素，已知其最高价氧化物对应水化物的酸性强弱顺序是：
HXO4>H2YO4>H3ZO4，则 下列各判断正确的是[ ]
A．原子半径：X>Y>Z
B．单质非金属性：X>Y>Z
C．气态氢化物的稳定性：X<Y<Z
D．原子序数：X>Y>Z
