Learning a second language is difficult at any age.The longer you wait to open that dusty French book，the harder it will get.Now，in a new study，scientists have pointed the exact age at which your chances of reaching fluency in a second language seem to drop：10.
   The study，published in the journal Cognition，found that it's " nearly impossible" for language
learners to reach native-level fluency if they start learning a second language after 10.But that doesn't seem to be because language skills go downhill. "It turns out you're still learning fast.It's just that you run out of time，because your ability to learn starts dropping at around 17 or 18 years old，" says study co-author Joshua Hartshorne，an assistant professor of psychology at Boston College.
   Kids may be better than adults at learning new languages for many reasons.Children's brains are more plastic than those of adults，meaning they're better able to adapt and respond to new information. " All learning involves the brain changing，" Hartshorne says， " and children's brains seem to be a lot more skilled at changing."
   These findings might seem discouraging，but it was encouraging for scientists to learn that the critical period of fluent language acquisition might be longer than they previously thought.Some scientists believed that the brief window closes shortly after birth，while others stretched it only to early adolescence.Compared to those estimates，17 or 18 when language learning ability starts to drop off —seems old.
   " People progress better when they learn by immersion （沉浸） rather than simply in a classroom.And moving to a place where your desired language is spoken is the best way to learn as an adult.If that's not an option，you can create an immersive environment by finding ways to have conversations with native speakers in their own communities，" Hartshorne says.By doing so，it's possible to become conversationally fluent —even without the advantage of a child's brain.

（1）What is the important finding of the new study？

A

A

A．The best age to learn a second language.
B．The possibility of speaking a fluent language.
C．The change of language skills over the time.
D．The great approaches to learning a language.
（2）Why do kids seem better than adults at learning new languages？

C

C

A．Their focus is language learning only.
B．They are more interested in languages.
C．They are more adaptable to new things.
D．Their brains always ignore big changes.
（3）What is Hartshorne's advice on becoming fluent in a second language？

B

B

A．Joining friends in their learning.
B．Turning to immersive learning.
C．Studying in a quiet classroom.
D．Training the brain to be like a kid's brain.
（4）From which part of a newspaper is the text most probably taken？

D

D

A．Science.
B．Travel.
C．Health.
D．Education.