题目

设NA表示阿伏伽德罗常数的值，下列说法中正确的() A．常温下，42 g C2H4和C4H8的混合物中含有的碳原子数为3 NA B．58.5 g氯化钠固体中含有NA个氯化钠分子； C．标况下，11.2 L己烷所含的分子数为0.5 NA； D．将16gO2与64gSO2在一定的条件下充分反应生成的SO3分子数为NA 答案：A---What were you doing when she dropped in? ---I for a while and______ some reading.A.was playing; was going to doB.played; didC.had played; was going to doD.had played; did