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问题 选择题

类推是化学学习中常用的方法．以下类推结果正确的是（　　）

A．淀粉遇到碘水呈蓝色，所以与碘水作用呈现蓝色的物质中含有淀粉

B．酸碱中和反应生成盐和水，所以生成盐和水的反应一定是中和反应

C．有一些金属与稀硫酸反应放出气体，所以与稀硫酸反应放出气体的物质是金属

D．燃烧一般都伴随发光和放热现象，所以有发光和放热现象的变化都是燃烧

答案

A、淀粉遇到碘水呈蓝色，所以与碘水作用呈现蓝色的物质中含有淀粉．正确；

B、生成盐和水的反应不一定是中和反应，例如稀盐酸和氧化钙反应能生成盐氯化钙和水，但是不是中和反应．错误；

C、与稀硫酸反应放出气体的物质不一定是金属，例如碳酸钠和稀硫酸反应能生成二氧化碳气体．错误；

D、有发光和放热现象的变化不一定是燃烧，例如电灯通电时发热、发光，但是不是燃烧．错误．

故选A．

单项选择题

符合契税减免税规定的纳税人，办理减免税手续的期限是签订产权转移合同后的 ( )天内。

A．5

B．7

C．10

D．15
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单项选择题

Proper arrangement of classroom space is important to encouraging interaction. Most of us have noticed how important physical setting is to efficiency and comfort in our work. College classroom space should be designed to encourage the activity of critical thinking. We may be approaching the twenty-first century, but step into almost any college classroom and you step back in time at least a hundred years. Desks are normally in straight rows, so students can clearly see the teacher but not all their classmates. The assumption behind such an arrangement is obvious. Everything of importance comes from the teacher.
With a little imagination and effort, unless desks are fixed to the floor, the teacher can correct this situation and create space that encourages interchange among students. In small or standard-size classes, chairs, desks, and tables can be arranged in a variety of ways. The primary goal should be for everyone to be able to see everyone else. Larger classes, particularly those held in lecture halls, unfortunately, allow much less flexibility.
Arrangement of the classroom should also make it easy to divide students into small groups for discussion or problem-solving exercises. Small classes with movable desks and tables present no problem. Even in large lecture halls, it is possible for students to turn around and form groups of four to six. Breaking a class into small groups provides more opportunities for students to interact with each other, think out loud, and see how other students’ thinking processes operate all essential elements in developing new modes of critical thinking. In courses that regularly use a small group format, students might be asked to stay in the same small groups throughout the course. A colleague of mine, John, allows students to move around during the first two weeks, until they find a group they are comfortable with. John then asks them to stay in the same seat, with the same group, from that time on. This not only creates a comfortable setting for interaction but helps him learn students’ names and faces.

The author mentioned John in Paragraph 4 in order to ______.

A. describe a good seat-arrange mode in courses with small group format
B. give an example that students stay in the same seat throughout the course
C. create a comfortable setting for interaction
D. learn students’ names and faces
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