题干

下列实验操作中,正确的是(  )

A:在氢氧化钠溶液中滴入少量的硫酸铜溶液,其中氢氧化钠是过量,来配制新制氢氧化铜

B:在稀氨水中逐渐加入稀的硝酸银溶液来配制银氨溶液

C:试管里加入少量淀粉,再加一定量的稀硫酸,加热3~4分钟,然后加入银氨溶液,片刻后管壁上有“银镜”出现

D:溴乙烷在氢氧化钠存在下进行水解后,加入硝酸银溶液,可检验溴离子的存在

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答案(点此获取答案解析)

A

同类题3

现代文阅读

                                                                                             《我的母亲》(节选)
                                                                                                          胡适
        家里虽然一贫如洗,但母亲情愿节衣缩食,省下钱来请了一位先生。我到十岁的时候,读的是“孟子见梁惠王”。到年底,父亲要“清算”我平日的功课。在夜里亲自听我背书,很严厉,桌上放着一根两指阔的竹板。我背向着他立着背书,背不出来的时候,他提一个字,就叫我回转身来把手掌展放在桌上,他拿起这竹板很重地打下来。我吃了这一下苦头,痛是血肉的身体所无法避免的感觉,当然失声地哭了,但是还要忍住哭,回过身去再背。不幸又有一处中断,背不下去;经他再提一字,再打一下。呜呜咽咽地背着那位前世冤家的“见梁惠王”的“孟子”!我自己呜咽着背,同时听得见坐在旁边缝纫着的母亲也唏唏嘘嘘地泪如泉涌地哭着。我心里知道她见我被打,她也觉得好像刺心的痛苦,对我表着十二分的同情,但她却时时从呜咽着的、断断断续续的声音里勉强说着“打得好”。她的饮泣吞声,为的是爱她的儿子;勉强硬着头皮说声“打得好”,为的是希望她的儿子上进。如今想起母亲见我被打,陪着我一同哭,那样的母爱,仍然使我感念着我的慈爱的母亲。背完了半本“梁惠王”,右手掌被打得发肿,有半寸高,偷向灯光中一照,通亮,好像满肚子装着已成熟的丝的蚕身一样。母亲含着泪抱我上床,轻轻把被窝盖上,向我额上吻了几吻。
        当我八岁的时候,二弟六岁,还有一个妹妹三岁。三个人的衣服鞋袜,没有一件不是母亲自己做的。她还时常收一些外面的女红来做,所以很忙。记得有一个夏天的深夜,我忽然从睡梦中醒了起来,因为我的床背就紧接着母亲的床背,所以从帐里望得见母亲独自一人在灯下做鞋底,我心里又想起母亲的劳苦,辗转反侧睡不着,很想起来陪陪母亲。于是想出一个借口来试试看,便叫声母亲,说太热睡不着,要起来坐一会儿。出乎我意料之外的,母亲居然许我起来坐在她的身边。我眼巴巴地望着她额上的汗珠往下流,手上一针不停地做着布鞋——做给我穿的。这时万籁俱寂,只听得嘀嗒的钟声和可以微闻得到母亲的呼吸。我心里暗自想念着,为着我要穿鞋,累母亲深夜工作不休,心上感到说不出的歉疚,又感到坐着陪陪母亲,似乎可以减轻些心里的不安。当时一肚子里充满着这些心事,却不敢对母亲说出一句。现在我的母亲不在了,她始终不知道她这个小儿子心里有过这样的一种不敢说出的心理状态。

同类题4

阅读理解

    I've loved my mother's desk since I was just tall enough to see above the top of it as Mother sat doing letters. Standing by her chair, looking at the ink bottle, pens, and white paper, I decided that the act of writing must be the most wonderful thing in the world.

    Years later, during her final illness, Mother kept different things for my sister and brother. “But the desk,” she said again, “is for Elizabeth.”

    I never saw her angry, never saw her cry, I knew she loved me; she showed it in action. But as a young girl, I wanted heart-to-heart talks between mother and daughter. It never happened. And a gulf opened between us. I was “too emotional”. But she lived “on the surface”. As years passed and I had my own family, I loved my mother and thanked her for our happy family. I wrote to her in careful words and asked her to let me know in any way if she chose that she did forgive me. I posted the letter and waited for her answer. None came. My hope turned to disappointment, then little interest and, finally, peace—it seemed that nothing happened. I couldn't be sure the letter had even got to Mother. I only knew that I had written it, and I could stop trying to make her into someone she was not.

    Now the present of her desk told me, as she'd never been able to, that she was pleased that writing was my chosen work. I cleaned the desk carefully and found some papers inside—a photo of my father and a one-page letter folded and refolded many times. She had given me an answer in a way she chose. Mother, you always chose the act that speaks louder than words.