题型:问答题 简答题 He was out of work due to the global financial crisis; he was sad and discouraged, feeling that he _ his family.A.failedB.abandonedC.ignoredD.betrayed 查看答案
题型:问答题 简答题 我国在砷化镓太阳能电池研究方面国际领先.砷(As)和镓(Ga)都是第四周期元素,分别属于ⅤA和ⅢA族.下列说法中,不正确的是( )A.原子半径:Ga>As>PB.热稳定性:NH3>PH3>AsH3C.酸性:H3AsO4>H2SO4>H3PO4D.Ga(OH)3 可能是两性氢氧化物 查看答案