Babies are surrounded by human language，always listening and processing.Eventually，they put sounds together to produce a "Daddy" or a "Mama".But what still confuses neuroscientists is exactly how the brain works to put it all together.
   To figure it out，a team of researchers turned to a frequent stand-in（代替）for babies when it comes to language learning：the song-learning zebra finch. "We've known songbirds learn their song by first forming a memory of their father's song or another adult's song.Then they use that memory to guide their song learning，" said Neuroscientist Todd Roberts. "It's been a long-term goal of the field to figure out how or where in the brain this memory is.This type of imitative learning that birds do is very similar to the type of learning that we engage in regularly—particularly when we're young，we use it to guide our speech learning."
   Roberts and his team had a feeling that the interface（交叉區(qū)域）between sensory areas and motor areas in the brain was critical for this process，and they focused on a group of brain cells called the NIf.
   "In order to prove that we could identify these circuits，we thought if we could implant a false memory." First，they used a virus to cause the neurons（神經(jīng)元）in the birds' NIf to become sensitive to light.Then，using a tiny electrode as a flashlight，they activated（激活）the neurons.The length of each pulse of light corresponded with the amount of time the neurons would fire.And the birds' brains interpreted that time period as the length of each note.
   Soon enough，the birds began to practice the notes they had learned，even though they never really heard the sounds.Amazingly，the birds produced them in the correct social situations.The researchers say this is the first time anybody has found exactly a part of the brain necessary for generating the sorts of memories needed to copy sounds.
   "This line of research is going to help us identify where in the brain we encode memories of relevant social experiences that we use to guide learning.We know that there are several neurodevelopmental disorders in people that have really far-reaching effects on this type of learning."

（1）The zebra finch is researched because its song-learning mode

C

C

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A．decides whether it will sing songs
B．helps it to say "Daddy" or "Mama"
C．is like the way babies learn speech
D．reflects its talent for imitating its father's song
（2）What does the underlined word "it" in Paragraph 2 refer to？

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C

A．The interface in the brain.
B．Guidance from adults.
C．Imitative learning type like birds'.
D．The way of regular learning.
（3）What can we learn from the research led by Roberts？

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A

A．Scientists activated some neurons by using an electrode.
B．A bird only sings what it heard before.
C．The brain produces tiny electrodes.
D．Birds are sensitive to light.
（4）What do the Roberts' team expect of this line of research？

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C

A．A change in our way of listening and processing.
B．A chance to have relevant social experiences.
C．A better knowledge of the secrets of learning.
D．Identification of neurodevelopmental disorders.