Нужно диалог о Байкале на английском языке.

Учитель: Our dear guests and the participants of the annual ecological conference! Today you are going to be ecologists. And we’ll try to unite our efforts in solving ecological problem. But before starting our conference try to guess what ecological problems we are going to talk about today. And the theme of our conference will be the following. Try to guess. Look at the pictures. Think. Now, begin discussing with your shoulder partners. I see that you are ready. Let’s listen to your suppositions. What do you see?
Учащийся: A sea, a river, an ocean, a lake. 
Учитель: How can they be called in one word?
Учащийся: Water.