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Listening to Birdsong"的相关试题:
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Listening to Birdsong
A male zebra finch chirps away to himself. Suddenly he notices a female bird nearby.He realizes he has an audience and immediately changes his song. Can the female tell the difference in his perfonnance?According to a new study,the female zebra finch knows.And she prefers the special trills he creates when he sings to her. A male zebra finch changes his song when singing to a female in ways that people can barely detect.But the female finch can tell the difference.
Scientists had noticed slight variations in the songs of male zebra finches based on whether they were singing alone or whether there was a female(and potential mate)nearby.With an audience,the males sped up the pace of their songs and controlled the notes they used.
For this study,researchers Sarah C .Woolley and Allison Doupe at the University of California,San Francisco decided to focus attention on the listening females,which have not been well studied in the past.
In the study,Woolley and Doupe set up,a long cage with a sound speaker at each end.One broadcast the sound of a male zebra finch singing to himself,like someone singing in the shower.The other speaker broadcast a male performing for a female audience,as if he was giving a concert.
Female birds were placed between the two speakers.Some of the birds had mates.Others didn't. The females shifted around a bit,and then most of them hopped over to sit beside just one speaker. All the birds that made a clear choice liked songs meant for a female audience,even if they'd never met the male.
Mated females also had a chance to listen to two different performance songs,one from an unknown male,and one from their mate .They spent more time listening to the concert version of their mates' songs.This suggests that after a while,females learn to recognize-and prefer-the songs of their mates.
Scientists then studied the brains of the females.They found certain areas of the brain perked up when the birds listened to the concert songs.These brain areas may be involved in recognizing and evaluating the songs,and storing the memories of them.
This research deals with what's called directed communication,when the communicator,or sender,focuses the message for a specific audience.One example is the way moms speak to their babies. Mothers around the world use the same sort of high-pitched sing-song chatter,and the babies respond best to those sounds.Songbirds are one of the only other species known to learn their communication,in this case their songs.
Which of the following can best reflect the theme of the passage?
A.Chirping away.
B.Birdsongs as communication.
C.Zebra finches and their life.
D.Enjoying birdsongs.
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第三篇
Listening Device Provides Early Landslide（山崩；地滑；塌方）Warning
A device that provides early warning of a landslide by monitoring vibrations（振动）in soil is being tested
by UK researchers,The device could save thousands of lives each year by warning when an area should be
evacuated（疏散，撤走）,the scientists say. Such natural disasters are common in countries that experience
sudden, heavy rainfall (降雨，降雨量), and can also be triggered by earthquakes and even water
erosion（腐蚀，侵蚀）.
Landslides start when a few particles of soil or rock within a slope start to move,hut the early stages can
be hard to spot.Following this initial movement,"slopes can become unstable in a matter of hours or
minutes,"says Nell Dixon at Southborough University,UK. He says。warning system that monitors this
movement"might be enough to evacuate a block of flats or clear a road,and save lives".
The most common way to monitor a slope for signs of an imminent（即将发生的） landslide is to watch
for changes in its shape. Surveyors can do this by measuring aside directly,or sensors（传感器）sunk into
boreholes（钻孔，井眼）or fixed above ground can be used to monitor the shape of a slope. Slopes can,
however,change shape without triggering a landslide,so either method is prone to causing false alarms.Now
Dixon's team has developed a device that listens for the vibrations caused when particles begin moving
within a slope.
The device takes the form of a steel pipe dropped into a borehole in a slope.The borehole is filled in
with gravel（砾，沙砾，砾石）around the pipe to help transmit high-frequency vibrations generated by particles
within the slope.These vibrations pass up the tube and are picked up by a sensor on the surface.Software
analyses the vibration signal to determine whether a landslide may be imminent.
The device is currently being tested in a 6-metre-tall artificial clay embankment（堤岸）in Newcastle,
UK.Early results suggest it should provide fewer false positives than existing systems.Once it has been
carefully and thoroughly tested,the device could be used to create a complete early-warning system for
dangerous slopes.
"Locations with a significant risk of landslides could definitely benefit from a machine like this,"says
Adam Poulter,an expert at the British Red Ci?oss,"As long as it doesn't cost too much."But,Poulter adds
that an early-warning system may not be enough on its own."You need to have the human communication."
he says,"Making systems that get warnings to those who need them can be difficult."
According to the context,what does the word"positives"in the fifth paragraph mean?
A.Positive electric charges.
B.Evidences.
C.Warnings.
D.Predictions.
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Just one hour's listening to an MP3 player can damage hearing,claim scientists.It causes temporary changes in hearing sensitivity which may lead to long-term harm,according to a new study.
The findings show over -stimulation of hair cells within the ear occurs even at varying volume levels for short periods of time.The study of almost 60 young people carried out by researchers at Ghent University,Belgium,is published in the Archives of Otolaryngology -Head&Neck Surgery journal.
It follows previous warnings from doctors that using MP3 players at high volumes with earphones that fit into the ear canal could lead to loss of hearing. In the latest study,21 people aged 19 to 28 years were exposed to pop and rock music using MP3 players at varying volumes for one hour. A second group of 28 men and women were a control group who were not exposed to MP3 music.
Hearing tests were carried out before and after the exposure,which found significant threshold or emission shifts were observed between almost every session of the noise exposure group compared with the control group.Lead researcher Hannah Kempler said:Excessive noise exposure can lead to metabolic and mechanical effects resulting in alterations of the structural elements of the inner ear that contains auditory sensory cells or"hair cells".
The European Commission has warned up to 10% of 30-year-old would have to wear a hearing device within the next decade because they listen to music too loudly through headphones.Surveys showed more than 90% of young people in Europe and the U.S.used MP3 players,often for several hours a day at maximum volume.Hearing experts recommend the 60/60 rule一listening to MP3 players for no more than 60 minutes at a time at 60% of maximum volume.Concern among EU health and safety officials has led to plan to ensure all MP3 players have the same maximum volume of 85 decibels(d
B)一although users may be able to individually override it at their own risk.
In the "60/60rule" (Para.5),the latter"60"stands for 60% of maximum volume.
A.Right
B.Wrong
C.Not mentioned
