答案　16.D　17.B　18.A　19.C　20.E

Ⅰ.Do you know the eight planets circling around the sun in our solar system？If so，please match them with the Chinese meaning.

1．Uranus　　　　　　 A．水星

2．Venus B．金星

3．Earth C．海王星

4．Mars D．天王星

5．Mercury E．木星

6．Jupiter F．地球

7．Neptune G．火星

8．Saturn H．土星

答案　1.D　2.B　3.F　4.G　5.A　6.E　7.C　8.H

Ⅱ.What do you know about the origin of life on the earth?

答案　略

Ⅰ.Skim the text and choose the best answer.

The text mainly tells us .

A．how the earth came into being

B．the development of humans

C．the formation of the earth and the development of life on it

D．how life appeared on the earth

答案　C

Ⅱ.Match each paragraph with its main idea.

Para.1　　　A．How humans appeared and what effects they had on the earth.

Para.2 B．Water is very important to life on the earth.

Para.3 C．How the earth formed.

Para.4 D．How the plants and animals on the earth developed.

Para.5 E．It is widely accepted that the universe began with a "Big Bang"．

答案　Para.1：E　Para.2：C　Para.3：B　Para.4：D

Para.5：A