32．Do you know all birds protect （1）
（they） by listening and watching out for danger？At the（2）
（small） sign of it，they will fly away.Birds that cannot fly are often able （3）
（swim） fast，or run quickly.Some birds make themselves look （4）
（big） and more dangerous by fluffing their feathers.
Another important （5）
（protect） for many birds is their colours.Their feathers often have colours that match the things around their nests.Some birds change colours with the seasons.In winter they are white（6）
（match ）the snow.In summer they are brown to match the ground.
People sometimes kill the birds without meaning to.When people cut down forests （7）
（build） houses and factories，they destroy the homes and food of birds.If the birds have nowhere else to go and nothing to eat，they （8）
（die）out.
Pollution may cause some birds to die.Birds that eat fish from polluted water get poison in their bodies.Then they cannot lay healthy eggs.New birds can't born.
Now people protect birds by passing the laws to control （9）
（hunt）and pollution，by setting up some special parks where all the birds are safe from hunters，and by teaching people （10）
（care）about birds rather than kill them.
