Anne usually was only willing to help those who suffered from the same disease as she did.
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By means of __________ (being young and being old) the author reveals the advantages of being old.
由于受工作面、自由面的限制,以及控制开挖断面轮廓形状和尺寸的要求,按炮孔的作用可将炮孔分为掏槽炮孔、崩落炮孔和周边炮孔。()
N2O3 的分解反应 N2O3 (g) → NO2 (g) + NO (g)是一级反应,反应速率常数 k = 3.2×10-4 s-1 。若初始浓度 [N2O3]=1.00 mol·L-1 ,则N2O3浓度减至 0.125 mol·L-1 需 ()小时。