三位以上的数字时，从右向左依次三位用逗点隔开，英文数字中的每一个逗点的读法也要牢记：第一个逗点前读"thousand"，第二个逗点前读"million"，第三个逗点前读"billion"。

Examples：

1,234 读作：one thousand, two hundred and thirty-four

4,567,809 读作：four million, five hundred and sixty-seven thousand, eight hundred and nine

5,678,120,000 读作：five billion, six hundred and seventy-eight million, one hundred and twenty thousand。

1. 在表达某物长、宽、高等时，要用此结构：物+be+数词+单位词+形容词，如：

The Yangtze is 6300 kilometers long. The building is 150 meters high. The road is only two meters wide. A 5-meter-wide river 一条五米宽的河。

2. 以上结构可以互换为：The length (long的名词)of... ......的长度；The height (high的名词)of... .......的高度；The width(wide的名词) of...... .......的宽度；The depth(deep的名词) of，.....的深度；deeply，副词，深深地，I am deeply moved by the film. 我被这部电影深深地感动了。

The ruler is 20cm long. =The length of the ruler is 20cm. =The ruler is 20cm in length.

3. 对长、宽、高等提问要用how long, how wide, how high(建筑物、山的高)，how tall（人和动物的高）。How high is the building?

4. 比较级和最高级的转化：The Pacific Ocean is the biggest in the world. =The Pacific Ocean is bigger than any other ocean. =The Pacific Ocean is bigger than all the other oceans. =No ocean is as big as the Pacific Ocean. (any other+名词单数，而all the other+名词复数)。

5. population 人口；人口数量，The population of...is..., ......的人口

The population of China is over (more than) 1.3 billion. 中国有十三亿多人口。

对人口数量提问要用 What's the population of......? What's the population of Japan?

表示人多时要用large或big；人少时用small。

China has the biggest population in the world.世界上中国人口最多。

The population of Japan is much smaller than that of China. 日本的人口要比中国少得多。

6. feel free 随意，不要拘束； Feel free to do sth 随便做某事

Feel free to as k questions if you don't understand. 你要是不懂，可以随便提问。

7. talk about the parts of the Great Wall from the Ming Dynasty, 谈论明代以来修的长城

8. ancient 古代的，古老的 Rome is one of the ancient countries. 罗马是古老的国家之一。

9. Asia 亚洲 in Asia 在亚洲；形容词为Asian；Asian countries 亚洲国家。

10. on the wall 和 in the wall 在墙上; 前者指在墙的表面，如黑板，画等；后者指在墙的里面，如门窗，钉子，洞等。

11. amazing 和amazed What she said made me amazed. Be amazed at 对......大为惊奇（-ed形容词和-ing形容词）

12. protect 保护 Protecting environment is our duty. 保护环境是我们的责任。

Protect......from......保护......免受.......Mothers always protect their children from being harmed.母亲们总是保护她们的孩子免受伤害。

13. The main reason was to protect their part of the country. 主要原因是保护他们的部分国土。（不定式表示目的）。如：As students, our job is to learn all the subjects well. 作为学生，我们的工作是要把所有的科目学好。

14. one of the oldest countries历史最悠久的国家之一，one of the word's most dangerous sports世界最危险的运动之一，one of the most popular places最受欢迎的地方之一（one of +最高级+名词复数）；one of the main reasons主要原因之一