20．Worried about the loss of rainforests and the ozone layer？Well，neither of those is doing any worse than a large majority of the 6，000 to 7，000 languages that remain in use on Earth.One half of the survivors will almost certainly be gone by 2050，while 40% more will probably be well on their way out.In their place，almost all humans will speak a small number of languages——Mandarin，English，Spanish.
Linguists（語言學(xué)家）know what causes languages to disappear，but what's less often remarked is what happens on the way to disappearance：languages' vocabularies，grammars and expressive potential all disappear. "Say a community goes over from speaking a traditional Aboriginal（土著的）language to speaking a Creole，" says Australian Nick Evans，a language experts， "you leave behind a language where there's very fine vocabulary for the landscape.All of that is gone in a Creole.As speakers become less able to express the wealth of knowledge that has filled ancestors' lives with meaning over thousands of years，it's no wonder that communities tend to become weakened."
Due to the huge losses，some linguists struggle against the situation，for example，training many documentary linguists in language-loss hotspots such as West Africa and South America.
However，not all approaches to the preservation of languages will be particularly helpful.Some linguists are boasting（自夸）of more and more complicated means of recording languages：digital recording and storage，the Internet and mobile phone technologies.But these are encouraging the quick style of recording trip：fly in，switch on digital recorder，fly home，download to hard drive，and store gathered material for future research.That's not quite what some endangered-language experts have been seeking.Michael Krauss from the University of Alaska complained openly that linguists are playing with technology research while most of their raw data is disappearing.
Who is to blame？Linguists who go out into communities to study，document and describe languages，argue that theoretical linguists，like Noam Chomsky，who draw conclusions about how languages work，have had so much influence that linguistics has largely ignored the continuing disappearance of languages.
（1）Why does the author mention rainforests and the ozone layer in Paragraph 1？
A．To highlight they are of great importance.
B．To show their connection with language loss
C．To indicate anxiety about environmental issues.
D．To introduce the topic concerning language loss.
（2）What does Nick Evans say about the effects of language disappearance？
A．People find it hard to describe their culture.
B．Vocabularies have to be changed.
C．People tend to turn to ancestors more
D．Focus is switched on new grammars.
（3）What has Michael Krauss pointed out？
A．Digital age further promotes some endangered languages.
B．An instant approach to language recording may not work.
C．Linguists have made poor use of improvement in technology.
D．Linguists' quick style of recording trip should be encouraged.
（4）What can be concluded from the text？
A．By 2050 only 600 to 700 languages will remain.
B．Local languages are preserved perfectly in West Africa.
C．Theoretical linguists may be responsible for the loss of languages.
D．Linguists have come a long way to save endangered languages.
