【单选题】下列说法正确的是
B.
海带中碘元素提取时氧化滤液中的I - 时应加入过量氯水
C.
检验火柴头中的氯元素,可把燃尽的火柴头浸泡在少量水中,片刻后取少量溶液于试管中,加亚硝酸钠、AgNO 3 溶液和稀硝酸
D.
金属钾、钠和白磷等暴露在空气中易燃烧,所以金属钾、钠和白磷应保存在煤油中
【单选题】关于木结构的防火,有一些的理解: Ⅰ.两座木结构之间,建筑的防火间距与外墙门窗洞口的开洞面积有关。 Ⅱ.由于木结构的可燃性,故对建筑物内填充材料的可燃性能可不作要求。 Ⅲ.当梁为难燃烧体时其耐火极限为1.00h。 Ⅳ.因防火要求,木结构房屋不能超过三层。 试问,下列何项的全部内容都是正确的理解?
【单选题】It is said that Sally's been painting for years since she was a little girl, ______?
【单选题】She made a few mistakes playing the violin, but you should make ____ for her since she’s only been playing for a year.
【多选题】关于民用建筑的防火间距的说法,正确的是( )。
A.
相邻两座单、多层建筑,'-3相邻外墙为不燃性墙体且无外露的可燃性屋檐,每面外墙上无防火保护的门、窗、洞口不正对开设且面积之和不大于该外墙面积的5%时,其防火间距可按规定减少20%
B.
相邻两座高度相同的一、二级耐火等级建筑中相邻任一侧外墙为防火墙屋顶的耐火极限不低于1.00h时.其防火间距可不限
C.
相邻两座建筑中较低一座建筑的耐火等级不低于二级,屋顶的耐火极限不低于1.00h,防火间距不应小于3.5m,对于高层建筑不应小于4m
D.
耐火等级低于四级的既有建筑,其耐火等级可按四级确定
E.
建筑高度大于100m的民用建筑与相邻建筑的防火间距,当符合规定允许减小的条件时,应减小
【简答题】It is said that Sally' s been painting for years since she was a little girl,_______ ? [A]isn' t she [B]hasn' t it [C]hasn ' t she [D] doesn ' it
【简答题】She made a few mistakes playing the violin,but you should make for her since she’s only been playinShe made a few mistakes playing the violin,but you should make ____ for her since she’s only been pl...