3．答案：C。此题主要考查英语中的分数表示法。英语中表示分数时，分母用序数词，分子用基数词，当分子大于1时，表示分母的序数词后要加s.

2．答案： B。此题主要考查序数词的运用。

2. Both of the rules are broken. I want to buy a ______ one.　

　　 A. three　　　　　 B. third　　　　　 C. forth　　　　 D. /

3). --- Which is the smallest number of the four?　　　　　 --- _________.

　　 A. Two- thirds　　 B. A half　　　 C. A quarter　　 D. Three-fourths

4). Please write down the new words in the text of _______.

　　 A. Lesson Eleven　 B. the Lesson Eleven　 C. Lesson Eleventh

解析：1.基数词hundred, thousand, million, billion 等前有具体数字时，它们后面不能加s,若这些词后面有介词of (几百，成百上千) ，thousands of (几千，数千个)，millions of, billions of 前不可用数词修饰。但可用many, some, several 等修饰。故选答案D.

1. _______ Chinese are looking for ways to learn English well before Beijing　 2008 Olympic.　　　　　　

　A. Thousand　　　 B. Thousands　　　 C. Thousand of　　 D. Thousands of

9．其他用法：

1)基数词+单数名词+形容词构成合成形容词。如：一个五岁的男孩a five-year-old boy；　

　 一座800米长的桥an 800-metre-long bridge；女子400米接力girls'400-metre relay race。

2)具体数词+metre(s)／kilometre(s)／kilo(s)long ／ high ／tall ／deep ／away等。如：长江长6300公里。The Changjiang River is 6，300 kilometres long．

3)表示"几十岁"用序数词，eg. 在他三十几岁时　 in his thirties

4)倍数的表达：(一倍用once，两倍用 twice，两倍以上用基数词+times。如：5倍five times)。　

例如：He is as tall a boy as I.

He is a head taller than I .

He is two years older than I

China is four times as large as Europe.

I am twice as old as you. (=I am twice older than you. /I am twice the age of you.)

My books are twice as many as yours.

China is four times larger than Europe.(=China is four times the size of Europe.)

I pay twice as much as it was worth.

I pay twice as much for the house.

例题解析：举一反三，学的更轻松！

12.135 twelve point one three five 　　　　　　　　　

8．表示有小数的词用基数词。 　　　　　　　　　　　

7．表示百分数

5℅：five percent (per cent)， 0.8℅ zero point eight percent (per cent).

12.135 twelve point one three five

5.5 five point five