练习册

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    (将学生分成两人小组.练习1a的对话.选两组同学到讲台上表演.) T:OK, I’d like to ask two groups of students to act out the dialog. (表演之后.要同学们评论哪一组加分.该加多少分.) T: Which group do you think is the best? Ss:- T: How many points should they get? Ss: Two points. T: Great! Step 4 Practice 第四步 练习 【查看更多】

     

    题目列表(包括答案和解析)

    已知向FeCl3浓溶液中加入Na2CO3浓溶液，可以观察到产生红褐色沉淀和无色气体，写出该反应的离子方程式                          。
    从形式上看，Na2SO3和Na2CO3相似，那么Na2SO3和FeCl3之间的反应情况又如何呢？某化学研究性学习小组提出了两种可能：一是发生氧化还原反应：2Fe3＋＋SO32－＋H2O＝2Fe2＋＋SO42－＋2H＋；二是发生双水解反应：2Fe3＋＋3SO32－＋6H2O＝3Fe(OH)3(胶体)＋3H2SO3； 为了弄清楚发生的是那一种反应发生，同学们设计并实施了下列实验，请填写下列空白：
    实验Ⅰ：实验用品   Na2SO3浓溶液、BaCl2稀溶液、稀盐酸、试管若干、胶头滴管若干。从选择的药品分析，实验者设计这个实验的目的是                        。
    实验Ⅱ：取5mLFeCl3浓溶液于试管中，逐滴加入Na2SO3浓溶液，观察到溶液的颜色由黄色变为红棕色，无气泡产生，无沉淀生成，继续加入Na2SO3浓溶液至过量，溶液的颜色加深，最终变为红褐色。这种红褐色物质是             。向红褐色物质中逐滴加入稀盐酸至过量，可以观察的现象是                                。将溶液分成两等份，其中一份加入KSCN溶液，溶液变成血红色，反应的离子方程式为：                           。另一份加入BaCl2稀溶液，有少量白色沉淀生成，反应的离子方程式为：                                 。
    实验Ⅲ：换用稀FeCl3和Na2SO3溶液重复实验Ⅱ，产生的现象完全相同。
    由上述试验得出的结论是                                    。

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    两人相约在7:30到8:00之间相遇，早到者应等迟到者10分钟方可离去，如果两人出发是各自独立的，在7:30到8:00之间的任何时刻是等可能的，问两人相遇的可能性有多大  

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    将下列句子编排成一段完整通顺的对话。

    a．Anything to drink?
    b. What size would you like? Small,medium or large?
    c. A cup of green tea, please. That's all. Thanks.
    d. Would you like to order, please?
    e. Would you like a salad, too? We have nice vegetables.
    f. Yes. I'd like some beef noodles, please.
    g. What drinks do you have?
    h. Medium，please.
    i. OK. I'd like a green salad.
    j. We have orange juice, green tea and...

     顺序：_____________________________________

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    将下列句子排序，组成一段完整的对话。
    A. Yes,please.1 want a hat.
    B. Thirty dollars.
    C. What color do you want?
    D. How much is it?
    E. You're welcome.
    F. Can I help you?
    G. Black and white.
    H. I'll take it. Thank you.
    I. Here you are.
    正确顺序是: __________________________

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    将所给句子排列成一段通顺的对话。
    a. Did you make your New Year's resolution?
    b. How are you going to do that?
    c. Me? Oh, I'm going to learn to play the piano and I'm going to take piano lessons.
    d. Yes, I did. I'm going to get good grades next year.
    e. Really? Sounds interesting!
    f. Well, I'm going to study hard and do my homework every day. How about you?
    ____________________________

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