【单选题】听力原文: A good reader reads fast and understands most of what he or she reads. Although each person is different, most good readers share six characteristics. First, most good readers read a great deal....
【简答题】(6分)阅读下面的信息,推断元素及有关物质,按要求回答: 信息①:X、Y、Z、W是常见的短周期元素,其原子序数依次增大,且原子核外最外层电子数均不少于2。 (1)根据信息①,X一定不是 (填序号)。 A氢 B. 碳 C. 氧 D. 硫 信息②:上述四种元素的单质均能在足量的氧气中燃烧,所生成的四种氧化物中,有两种能溶于稀硫酸,三种能溶于浓氢氧化钠溶液,氧化物的相对分...