题目内容：

Songs that make our hearts happy can make them stronger too, US researchers reported on Tuesday.

They found that when people listened to their favorite music, their blood vessels (血管) dilated in much the same way as when they are laughing, or taking blood medications.

"We have a pretty impressive effect," said Dr Michael Miller, director of preventive cardiology (心脏病学) at the University of Maryland Medical Center in Baltimore.

"Blood vessel diameter improved," he said. "The vessel opened up pretty significantly. You can see the vessels opening up with other activities such as exercise." A similar effect is seen with drugs such as statins.

When blood vessels open up more, blood flows more smoothly and is less likely to form the clots (凝块) that cause heart attacks and strokes. "We are not saying to stop your statins or not to exercise but rather to add this to an overall program of heart health," said Miller, who presented his findings to a meeting of the American Heart Association in New Orleans.

Miller's team tested 10 healthy, non-smoking men and women, who were told to bring their favorite music. They spent half an hour listening to the recordings and half an hour listening to music they said made them feel anxious while the researchers did ultrasound tests designed to show blood vessel function.

Compared to their normal baseline measurements, blood vessel diameter increased 26 percent on average when the volunteers heard their joyful music. Listening to music they disliked — in most cases in this group heavy metal — blood vessels narrowed by six percent, Miller said.

Miller said he came up with the idea after discovering that laughter caused blood to literally flow more smoothly. "I asked myself what other things make us feel really good, besides calories from dark chocolate of course. Music came to mind. ... It makes me feel really good," he said.

Most of the volunteers chose country music but Miller said the style is not so important rather than what pleases each individual.

1. The underlined word dilate (in paragraph 2) is closest in meaning to “_____”.

A. widen             B. move               C. change              D. increase    

2. According to the passage, which of the following will NOT cause blood vessels to open up?

A. Taking exercise.                            B. Listening to unpleasant music.

C. Bursting into laughter.                       D. Taking drugs like statins.

3. It can be inferred from the passage that _____.

A. blood clots are caused by heart attacks and strokes

B. music is better than chocolate for your health

C. the style of music has different effects on different people

D. a person’s overall health is more influenced by how much exercise he gets

4. What is the passage possibly taken out from?

A. A scientific journal.                      B. A school textbook.

C. A medical brochure.                            D. A local newspaper.

5. What’s the best title of the passage?

A. Pleasant Music Cures              B. Research into Blood Vessel

C. Music and Heart Attack                   D. Music and Happiness