1、讲义3：数词一 数词的分类（数词分基数词和序数词）基数词是表示自然数列的词, 例如; one, two, three, four.序数词是表示先后顺序的词, 例如: first, second, third, fourth二 基数词和序数词的表示法1基数词单词的拼写：112为单词，1319都以后缀-teen结尾，20至90这样的整十数都以后缀-ty结尾，其他基数词中间加连字符号“-”再按照上述的变化进行。例：21twenty-one 56- fifty-six 85eighty-five三位数的构成为：几+百+and+末两位（或末一位）数例：132one hundred and thirty-
2、two205two hundred and five千以上的数字的读法：从后面往前，每三位数作为一个单位，分别为thousand, million.32, 548, 652, 读作：thirty two million, five hundred and forty eight thousand, six hundred and fifty two2. 序数词=基数词+th (1、2、3为 first, second, third)。但以下几种情况要注意：1) fifth (第五)，eighth (第八)，ninth (第九)，twelfth （第十二）2) 以ty结尾的基数词变词尾为tiet
3、h例：twentytwentieth, ninetyninetieth3)复合序数词只需要将相应基数词中最后一位变成序数词，其余不变。例：第二十一twenty-first第二百四十五two hundred and forty-fifth三基数词的用法：1、表示计量：表示事物的计量，即事物的长度、宽度、深度和高度，应采用基数词。如：It is 50 metres/kilometers/miles long (wide, deep, high).它有50米/千米/英里长（宽、深、高）。 2、表示编号：编号的数字如果过小，可用序数词或基数词表示；如果数字较大，通常用基数词表示。如：The tenth
4、 lesson=Lesson Ten 第10课Room 405 第405号房 Page 215 第215页No.14 Middle School 第14中学Telephone NO.5855806 电话： 5855806【重点】3、表示不确切的数字：基数词后面直接加上复数名词表示精确的数字，而基数词复数形式加上“of” 表示不确切的数字。如： five hundred students 500名学生hundreds of students 几百名学生millions of workers 成千上万的工人4、用基数词表示年龄和岁数1）表示年龄的主要句式如下： He is a boy of 10
5、yeas old. 他是个10岁的男孩子。 He is 10(years of age). 他10 岁。 He is a ten-year-old boy. 他是个10岁的男孩子。2) 介词in+ ones twenties (thirties) 表示 “在某人20多岁（30多岁）”。如：My father is in his fifties. 我爸爸50多岁。When he was in his forties, he began to learn English. 当他40多岁时，他开始学英语。【难点】5、表示年代：表示什么世纪，什么年代时，通常在数词后加s或s，并在年代前加冠词the ,
6、如1980s（20世纪80年代），读作：nineteen eighties. 如：His grandfather died in the 1970s。 他爷爷死于20世纪70年代。【重点】6、表示分数：分数的表达方式是：分子用基数词，分母用叙述词。分子是one时，母不必加s; 分子大于one时，分母要加s.如： one-fifth五分之一 two-thirds 三分之二 three-fourths四分之三7、表示百分数：百分数的表达方式是：基数词+ percent（单数形式）+of+名词。如：Thirty percent of the students in my class are from
7、 cities. 我班30%的学生来自城市。About 61 percent of the surface is covered by water. 大约61%的表面被水覆盖着。【重点】8. 有关倍数表示法两倍用twice, 三倍以上用数词+times, 要注意倍数在句子的位置。1）.主语+谓语+倍数（或分数）+ as + adj +as。例如：I have three times as old as you. 我有你三倍那么大。2）.主语+谓语+倍数（分数）+the size (amount,length) of 例如：The earth is 49 times the of the is
8、size of the moon. 地球是月球的49倍。3）主语+谓语+倍数（分数）+形容词（副词）比较级+than 例如：I have three times older than you.4）.by+倍数，表示增加了多少倍。 例如：The number of students in our class has been increased by four times now.我们班学生的数量已经增加了四倍。四随堂练习：( ) 1. There are _ days in a year. A. three hundreds sixty-five B. three hundreds and s
9、ixty-five C. three hundred and sixty-five D. three hundred and sixty five( ) 2. There are_ students in this school. A. eight hundreds and forty-six B. eight hundred and forty six C. eight hundred and forty-six D. eight hundred forty-six( ) 3. _people visit this museum every day. A. Hundred B. Hundre
10、ds C. Hundred of D. Hundreds of( ) 4. There are two_ people in the meeting room. A. hundred B. hundreds C. hundreds of D. hundred of( ) 5. Every year _ watch NBA on TV. A. million people B. millions of people C. millions people D. million of people( ) 6. _ trees have been planted in our school in th
11、e past 10 years. A. Thousands of B. Two thousands C. Thousand of D. Two thousand of( ) 7. Look! There are _ in the sky. A. thousand stars B. thousand of stars C. thousands of stars D. thousands of star( ) 8. My brother is in_. A. Three Class, One Grade B. Class Three, Grade One C. Grade One, Class Three D. class three, grade one( ) 9. We are going to learn_ this term. A. book six B. six book C. the book six D. Book Six( ) 10. Please turn to_. Lets read the text aloud. A. Page Two B. the page two C. second page D. page second
