Have you ever wondered why birds sing? Maybe you thought that they were just happy. After

Have you ever wondered why birds sing? Maybe you thought that they were just happy. After all, you probably sing when you are happy.

Some scientists believe that birds do sing some of the time just because they are happy. However they sing most of the time for a very different reason. Their singing is actually a warning (警告) to other birds to stay out of their territory.

Do you know what a “territory” is? A territory is an area that an animal, usually the male, claims (声称) as its own. Only he and his family are welcome there. No other families of the same species are welcome. Your house is your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you, you might shout. Probably this would be enough to frighten him away.

If so, you have actually frightened the stranger away without having to fight him. A bird does the same thing. But he expects an outsider almost any time, especially at nesting (筑巢) season. So he is screaming (尖叫) all the time, whether he can see an outsider or not. This screaming is what we call a bird’s song, and it is usually enough to keep an outsider away.

Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs.

You can see that birds have a language all their own. Most of it has to do with attracting mates and setting up territories.

1Some scientists believe that most of the time bird’s singing is actually ________.

       Aan expression of happiness                   Ba way of warning

       Can expression of anger                         Da way of greeting

2What is a bird’s “territory”?

       AA place where families of other species are not accepted.

       BA place where a bird may shout at the top of its voice.

       CAn area for which birds fight against each other.

       DAn area which a bird considers to be its own.

3Why do birds keep on singing at nesting season?

       ABecause they want to invite more friends.

       BBecause their singing helps frighten outsiders away.

       CBecause they want to find outsiders around.

       DBecause their singing helps get rid of their fears.

4How does the writer explain birds’ singing?

       ABy comparing birds with human beings.

       BBy reporting experiment results.

       CBy describing birds’ daily life.

       DBy telling a bird’s story.

答案

BDBA

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