题目内容：

    Have you ever wondered why certain pop songs just make you feel so good?

Researchers studying the question found that the right combination of uncertainty and surprise is what gives listeners the most pleasure.

The study, published in the journal Current Biology, involved an analysis of 80,000 chords( 和弦)in 745 pop songs from the US Billboard “Hot 100” chart between 1958 and 1991.

The researchers - from institutes in Germany, Norway, Denmark and the UK - used a machine-learning model to quantify the level of uncertainty and surprise of these chords, and then asked 39 adult volunteers to rate how pleasurable they found each series of chords.

Each song was stripped of its melody and lyrics(歌词)so that only chord progressions were left and the results couldn’t be influenced by other associations to the songs that listeners might have had.

They found two things: that participants got greater pleasure when they were relatively certain what would happen next but then were surprised by an unexpected chord progression. However, the same number of participants found it pleasant when they were uncertain as to what would follow, and then the subsequent chords were more familiar to them.

“It is fascinating that humans can get pleasure from a piece of music just by how sounds are ordered over time,” Vincent Cheung, the lead researcher on the paper from the Max Planck Institute for Human Cognitive and Brain Sciences, Germany, said in a statement.

“Songs that we find pleasant are likely those which strike a good balance between knowing what is going to happen next and surprising us with something we did not expect. Understanding how music activates our pleasure system in the brain could explain why listening to music might help us feel better when we are feeling blue.”

Cheung told CNN that pleasure in music has a lot to do with what listeners expect. Previous studies had looked into the effects of surprise on pleasure, but he and his colleagues’ study also focused on the uncertainty of listeners’ predictions.

The findings may help improve artificial musical algorithms(算法)and could help composers write music or predict musical trends.

“The idea is that hopefully as a scientist analyzing these patterns of pleasure in humans, you can somehow work out where music can go next,” Peter Harrison, a researcher at Queen Mary University, London, who worked on the project, told CNN.

As part of the same experiment, the researchers also used brain imaging to locate the areas of the brain reflected in musical pleasure. They found the regions involved were the amygdala, the hippocampus and the auditory cortex, which process emotions, learning and memory, and sound, respectively.

Cheung added that another part of the brain, the nucleus accumbens - which processes reward expectations - was perhaps responsible for “directing our attention towards the music so that we will try to find out what will happen next.”

1.This passage mainly deals with _____.

A.how composers create pop music trends B.why popular music makes people happy

C.what kind of music makes people most happy D.which part of the brain produces happy music

2.The underlined words in Paragraph 5 have the closest meaning to _____.

A.reserved B.restored C.removed D.refreshed

3.We can learn from the passage that __________.

A.pleasure in music is connected with listeners’ expectations

B.findings of this study are of little help to music composing

C.the regions of the brain mentioned process music composing

D.only uncertainty followed by familiarity can bring about pleasure