题目

下列关于金属铝的叙述中，正确的是A．铝是地壳中含量最多的元素B．铝是比较活泼的金属，在化学反应中容易失去电子，表现氧化性C．与铝反应产生H2的溶液一定呈酸性D．铝箔在空气中受热可以熔化，由于氧化膜的存在，熔化的Al 并不滴落 答案：DIt has been announced that all the students ______ put on the masks before going to school in case they are infected with SARS virus.A．shallB．willC．needD．may