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8.“水中柳影引他长”中的“引”字有什么妙处?(2分)

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新  柳

杨万里

柳条百尺拂银塘,且莫深青只浅黄。

未必柳条能蘸水,水中柳影引他长。

7.诗中的“新柳”有什么特点?(2分)

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2、分组问题例2:从1、3、5、7、9和2、4、6、8两组数中分别选出3个和2个数组成五位数,问这样的五位数有几个?

   (本题我是先让学生计算,有很多同学得出的结论是P ×P )

   ① 仔细审题:先由学生审题,明确组成五位数是一个排列问题,但是由于这五个数来自两个不同的组,因此是一个"分组排列问题",然后对题目进行等价转换。

   ② 转换题目:在学生充分审题后,我让学生自己对题目进行等价转换,有一位同学A将题目转换如下:从班级的第一组(12人)和第二组(10人)中分别选3位和2位同学分别去参加苏州市举办的语文、数学、英语、物理、化学竞赛,问有多少种不同的选法?

   ③ 解决问题:接着我就让同学A来提出选人的方案同学A说:先从第一组的12个人中选出3人参加其中的3科竞赛,有P ×P 种选法;再从第二组的10人中选出2人参加其中2科竞赛有P ×P 种选法;最后由乘法原理得出结论为(P ×P )×(P ×P )(种)。(这时同学B表示反对)

   同学B说:如果第一组的3个人先选了3门科目,那么第二组的2人就没有选择的余地。所以第二步应该是P ×P .(同学们都表示同意,但是同学C说太蘩)

   同学C说:可以先分别从两组中把5个人选出来,然后将这5个人在5门学科中排列,他列出的计算式是C ×C ×P (种)。(再次通过互相讨论,都表示赞赏)

   这样原题的解答结果就"浮现"出来C ×C ×P (种)。

   ④ 老师总结:针对这样的"分组排列"题,我们多采用"先选后排"的方法:先将需要排列的对象选定,再对它们进行排列。

   以上是我一节课两个例题的分析过程,旨在通过这种方法的尝试(教学效果比较明显),进一步活跃课堂气氛,更全面地调动学生的学习积极性,发挥教师的主导作用和学生的主体作用,让学生在互相讨论的过程中学会自己分析转换问题,解决问题。

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   The Alps rise over four countries.

   The Philippines are in the Pacific Ocean.

   Niagara Falls are not as high as Victoria Falls.

   The Andes are in South America, and the Alps are in Europe.

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   A great number of factories have been set up here since 1987.

   The number of the students is small in this school, but a large number of books are lent at the library.

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   What disappointed us most was his refusal.

   What they want are financial aids.

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   Lots of food is going to waste.

   Lots of people are waiting outside.

   There is a lot of air in loose snow.

   A lot of visitors have been there.

   Plenty of the money comes from donations.

   Plenty of the members are willing to do the work.

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   The Smiths were also invited.

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   The English like to be with their family at Christmas.

   The Chinese are kind and friendly.

   当上述形容词转化为名词,作某种语言解时,谓语动词用单数,如:

   French is spoken in many countries.

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   A chemical works has been built here.

   There are two iron and steel works in our province.

   There is / are no means of learning what is happening.

   Is /Are there any other means of getting there?

   Every possible means has been tried since then.

   All possible means have been tried since then.

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