【简答题】2010年11月15日,上海静安区高层住宅发生大火,短时间内急速蔓延烧透整栋建筑物,元凶极有可能是施工队所使用的保温材料聚氨酯(PU)发泡塑料等易燃材料。回答下列问题: ⑴聚氨酯发泡塑料属于__________(填“天然有机高分子”或“合成有机高分子”)材料。根据这次火灾,可推测出聚氨酯发泡塑料所具有的一条化学性质是__________。 ⑵工人施工时溅落的电火花引发了这场特大火灾,电火花所起的作...
【单选题】下列对青海气候条件的的表述有误的一项是:()
B.
基本的气候特征为:干燥、少雨、多风、寒冷、日温差大
C.
冬长夏短、四季分明,气候区分布差异大垂直变化明显
D.
平均日照数为2350~2900小时,对农作物和牧草的生长有利
【简答题】My father was 44 and knew he wasn’t going to male it to 45. He wrote me a letter and hoped that something in it would help me for the rest of my life. Since the day 1 was 12 and first read his lett...
【单选题】下列核苷酸中,不可能存在于DNA结构中的是 [ ]
【简答题】2010年11月15日,上海静安区高层住宅发生大火,本次火灾在短时间内急速蔓延烧透整栋建筑物,元凶极有可能是施工队所使用的保温材料聚氨酯(PU)材料.由于事故现场违规使用大量尼龙网、聚氨酯泡沫等易燃材料,加上四个无证电焊工违章操作造成火灾的发生.据此,请回答下列问题: (1)聚氨酯泡沫塑料属于 (填“有机”或“无机”)材料. (2)火灾给人类的生命和财产造成巨大损失.如果我们的住房着火,是否要打开...
【单选题】下列核苷酸中,在DNA结构中不可能具有的是()
【简答题】2010年11月15日,上海静安区高层住宅发生大火,短时间内急速蔓延烧透整栋建筑物,元凶极有可能是施工队所使用的保温材料聚氨酯(PU)发泡塑料等易燃材料.回答下列问题: (1)聚氨酯发泡塑料属于______(填“天然有机高分子”或“合成有机高分子”)材料.根据这次火灾,可推测出聚氨酯发泡塑料所具有的一条化学性质是______. (2)工人施工时溅落的电火花引发了这场特大火灾,电火花所起的作用是__...
【单选题】D My father was 44 and knew he wasn’t going to male it to 45. He wrote me a letter and hoped that something in it would help me for the rest of my life. Since the day 1 was 12 and first read his lette...
A.
lost his father when he was young
B.
worked hard before he read his father’s letter
C.
asked his father permission to believe in himself
D.
knew execty at thing his father wanted him to do