[单选题]— Excuse me, sir. Would you do me a favour— Of course. What is it— I _____ if you could tell me how to fill out this form.A. had wondered B. was wondering C. would wonderD. did wonder
[单选题]人们利用铁、铜、铝,由早到晚的时间顺序是 [ ]A.铁、铝、铜 B.铜、铁、铝 C.铝、铜、铁 D.铁、铜、铝
[单选题]— How do you usually go to work— I usually drive, but if it is fine, I ______ by bike.( )A. will go B. would go C. have gone D. had gone
[单选题]在下列这些药品中属于抗生素的是A.碘酒B.阿司匹林C.青霉素D.抗酸药
[单选题]下列表述正确的是①对含SO2、NO2等工业废气进行无害处理后,再排放到大气中可减少酸雨的产生②镁铝合金在冷的浓H2SO4中钝化③氧化镁、氧化铝可用来制造耐火砖和坩埚等④建设三峡大坝使用了大量水泥,水泥是硅酸盐材料⑤高压钠灯发出的黄光射程远,透雾能力强,故可做航标灯A.①②④⑤ B.①③④⑤C②③④D.全部
[单选题]What the children in the poor mountain village need ________ textbooks. [ ]A. is B. are C. hasD. have
[单选题]在第二次世界大战中,抗生素( )拯救了成千上万士兵的生命,当时被誉为与原子弹、雷达齐名的三大发明之一.A.青霉素B.阿司匹林C.红霉素D.吗啡
[单选题]金属冶炼中不会涉及到的反应类型是( )A.氯化还原反应 B.置换反应 C.分解反应D.复分解反应
[单选题]下列食物中富含碘元素的是( )A.米饭B.苹果C.瘦肉D.海带
[单选题]If city noises _____ from increasing, people _____ shout to be heard even at the dinner table20 yearsfrom now.[ ]A. are not kept;will have to B. are not kept;have to C. do not keep;will have to D. do not keep;have to
[单选题]地球上最大的储水库是什么?[ ]A.江湖 B.海洋 C.冰川 D.溪流
[单选题]The development of Chinas economy ________ since the 80s of last century. [ ]A. has been accelerating B. had acceleratedC.is acceleratingD. accelerated
[单选题]下列说法正确的是[ ]A.“乙醇汽油”是在汽油中加入乙醇生成的一种新化合物 B.淀粉、纤维素完全水解的产物互为同分异构体C.鸡蛋清中加入CuSO4溶液会产生盐析 D.煤油是石油的分馏产品,可用于保存少量金属钠
[单选题]— Where have you been— I in the heavy traffic. Otherwise I here earlier.[ ]A. got stuck; would have comeB. got stuck; wasC. have got stuck; would have comeD. Had got stuck; would come
[单选题]从石油分馏得到的固体石蜡,用氯气漂白后,燃烧时会产生含氯元素的气体,这是由于石蜡在漂白时与氯气发生过( )A.加成反应B.取代反应C.聚合反应D.催化裂化反应
[单选题]化学与生产、生活、社会密切相关,下列有关说法不正确的是( )A.绿色荧光蛋白质(GFP)是高分子化合物,其水溶液有丁达尔效应B.世博停车场安装催化光解设施,可将汽车尾气中的CO和NOx反应生成无毒物质C.绿色化学的核心是应用化学原理对环境污染进行治理D.高容量的储氢材料研究是推广应用氢氧燃料电池的关键问题之一
[单选题]下列说法正确的是 [ ]A.钢铁在海水中比在河水中更易被腐蚀,主要原因是海水含氧量高于河水B.蚕丝、羊毛和淀粉分别属于纤维素、蛋白质和多糖 C.不可用铝制餐具长时间存放酸性、碱性食物D.凡含有食品添加剂的食物对人体健康均有害,不宜食用
[单选题]下列试纸使用时, 不宜先用水润湿的是[ ]A.pH试纸 B.红色石蕊试纸C.淀粉碘化钾试纸 D.蓝色石蕊试纸
[单选题]某优质甜樱桃中含有一种羟基酸(用M表示),M的碳链结构无支链,分子式为C4H6O5；1.?34?g?M与足量的碳酸氢钠溶液反应,生成标准状况下的气体0.448?L.M在一定条件下可发生如下转化:M浓硫酸A.r2B足量NaOH溶液C(M、A、B、C分子中碳原子数目相同).下列有关说法中不正确的是[ ]A.M的结构简式为HOOC-CHOH-CH2-COOH B.B的分子式为C4H4O4Br2C.与M的官能团种类、数量完全相同的同分异构体还有2种D.C物质不可能溶于水
[单选题]I would have gone to visit him in the hospital had it been at all possible, but I ____ fully occupied the whole of last week.A. were B. had been C. have been D. was
[单选题]He was a bit nervous. He _________his spare breath with a soft sound that was almost heard by the audience.A.gave outB.let outC.picked outD.blew out.