Passage 5Questions 21 to 25 are

Passage 5
Questions 21 to 25 are based on the following passage.
There are about 150 Native American languages in Canada and the United States,and another 600-700 languages in Central and South America.We don't know exactly how many languages there are because not everyone agrees on the definition of language.If two languages are similar enough that speakers can usually understand each other,they are called dialects(方言)of the same language.For example,American English and British English are dialects.On the other hand,English and German are different languages,because even though they are related,an English speaker can't necessarily understand a German speaker.However,sometimes there are special cases.For example,Spanish and Italian speakers can often understand each other.And sometimes speakers of two dialects of English can hardly understand each other at all.So depending on how you count them,there are between 750-850 indigenous(土著的)languages spoken in North,Central,and South America.There are about half a million speakers of indigenous languages in Canada and the US,and as many as 25 million speakers in Central and South America.
Native American languages are endangered.If children stop learning their native language,the languages can die out just like endangered animals.Some Native American communities are bilingual(会说两种语言的)，but in most places parents have stopped teaching children their native language.In the past,the US and Canadian governments used to take Indianc children away from non-English-speaking homes,without their parents' permission,and put them into boarding schools.This was very painful for the children,so many parents stopped using their native languages to try and protect their children.Although this bad policy was abandoned,many Native Americans have grown up without their language,and it is difficult to try to learn a new language as an adult.Some communities are trying to ask elders to teadh the youngest generation the language before it is too late.
What can we do to help preserve Native American languages?If you are Indian,learn your language!More than anything else,this is in the hands of the kids.Young people can learn a language more quickly and easily than older people.Visit older relatives and record them talking.You can make a difference.If you are not Indian,you can still learn some words the same way you learn any other foreign language.You could even study languages when you grow up,and help Native American communities preserve their languages first-hand!
What has caused Native American languages to be endangered?
A、A past policy to force Native American children to learn English.
B、Their limited vocabulary for daily communication.
C、The pain and hardships in learning to speak them.
D、The low birth rate af Native American children.
【正确答案】：A