下列实验中,对应的现象以及结论都正确且两者具有因果关系的是( )
A:在空气中点燃纯净的氢气 ,火焰为淡蓝色,说明氢气能支持燃烧
B:高温下,将一氧化碳通过氧化铁粉末,黑色粉末变为红色,说明一氧化碳具有还原性
C:将铁丝和铜丝分别放入稀盐酸中,铁丝表面有气泡产生,铜丝表面无变化,说明铁的金属活动性比铜强
D:将二氧化碳通入紫色石蕊溶液中,紫色石蕊溶液变成红色,说明二氧化碳显酸性
阅读下面文字,按要求作文。
我国核潜艇之父黄旭华在回忆研制核潜艇经历时说:潜艇的重心和重量直接关系它的不沉性,所以要求特别苛刻,当时我们没有高科技手段控制,就想了个“土办法”一一在船台入口处摆了个磅秤,只要拿进船台的不管是什么都要过秤并记录在案;同样的,施工过程中拿出船台的任何东西也要称一称……几年来天天如此。
请根据你对材料的理解和感悟,写一篇不少于600字的文章。
要求:①题目自拟,立意自定。②除诗歌外,文体自选。③不得抄袭、套作。④文中不得出现你所在学校的校名,以及教职工、同学和本人的真实姓名。
列举森林的作用?
词汇运用 。根据句子意思,用括号中所给汉语提示或英语单词的适当形式填空。(每空一词)
1.The poster says more than one____ will attend the presentation. (导演)2.She had been very successful before ____ the film industry. (进入)3.Who do you think thought of that____ ending of the story? (令人惊讶的)4.We all know that he is always trying to do things____ . (不同地)5.The teachers often tell us not to do anything ____ the law. (反对)6.Audrey Hepburn is considered as one of Hollywood’s all-time ____ actresses. (great)7.My parents often remind me of the road____on my way to school every day. (safe)8.How do you like the film____ on the novel of Mo Yan? (base)9.It's said that young man went abroad for further education alone in his____ (20)10.We are not sure whether the victim was killed or he killed____ .(he)
有人说,FAMILY=(F)ather(A)nd(M)ather,(I)(L)ove(Y)ou。爱自己的父母,就应该( )①只要努力学习就是孝敬父母,其他无所谓②孝敬父母要做惊天动地的大事③理解体谅父母,做力所能及的事情④关心、尊重父母,经常和父母沟通