Cathy:What are you doing，Jack?

Jack:I`m just looking at this map of the world. I`m preparing for a geography class.

Cathy: There are no countries marked on the map.

Jack: No, there aren`t. This map just shows the geographical features(地理特征). Look at the Himalayan plateau（高原） with the highest peaks in the world.

Cathy: The thing that I find most surprising is that most of the world is covered with water. Compared to the oceans, most countries are tiny.

Jack: I find it incredible how millions of years of volcanic activity have created mountains thousands of metres tall.

Cathy: Rivers have created deep valleys and canyons.

Jack: The oceans and landscapes（地形） all influence our climate（气候）.

Cathy: It`s all so interesting. I`ll have to find more information about it on the internet. Or perhaps I should try and attend your geography class.