You shiver to keep warm. The heat that you make is made mostly in your muscles. The muscles make more heat when they are active. So one way of keeping warm is to move about, use your muscles. Another way is to shiver. When your body needs heat, the muscles tighten and loosen quickly. They become active. Just as you shiver to keep warm, so do birds.
Task 1. Imagine that you are preparing a project with your friend. You have found some interesting material for the presentation and you want to read this text to your friend. You have 1.5 minutes to read the text silently, then be ready to read it out aloud. You will not have more than 1.5 minutes to read it.
