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.

New Words：

botany ['bɔtəni] n. 植物学
botanist ['bɔtənist] n. 植物学家

Sample Sentences：

He studied botany at university.
People who study plants are called botanists.
In learning botany, I understand much about nature.
Zoology and botany are the two main branches of biology.

zoology [zu'ɔlədʒi] n. 动物学