New Words：

private ['praivit] adj. 私人的；个人的；私下的
pay a visit to v. 拜访；探望；去参观

Sample Sentences：

That's my private view.
I wish to have a private talk with you.
If you go to a private hospital you must pay.
The president is paying a private visit to Europe.
The hotel has 110 bedrooms, all with private bathrooms.

New Words：

illegal [i'li:gəl] adj. 不合法的；非法的；违法的

Sample Sentences：

It's illegal to carry guns in our country.
It's illegal for people under 17 to drive a car in Britain.
It's illegal to read people's private letters without permission.

New Words：

mankind [mæn'kaind] n. 人类

Sample Sentences：

Health is the best wealth for mankind.
Mankind can not live on the moon where there is no air and water.
Mankind must put an end to war, or war will put an end to mankind.
Each human being has to die, but mankind goes on world without end.

New Words：

extinct [iks'tiŋkt] adj. 灭绝的；绝种的；绝迹的；消亡了的

Sample Sentences：

All hopes were extinct.
Dinosaurs have been extinct for millions of years.
What a pity that this kind of rare animal has become extinct.
Have you ever thought that one day mankind would be extinct?

New Words：

zoology [zu'ɔlədʒi] n. 动物学
zoologist [zu'ɔlədʒist] n. 动物学家

Sample Sentences：

His father is an expert in zoology.
Botany is the study of plant life, and zoology is the study of animal life.

The zoologist has lived in the forest for ten years.
The zoologist had spent a long time living with monkeys.