Not all think laughter is the best medicine, but it seems to help．So scientists carried on a new study of diabetes （糖尿病） patients who were given a good dose of humor for a year to prove it．
Researchers divide 20 high-risk diabetic patients into two groups．Both groups were given standard diabetes medicine．Group L viewed 30 minutes of humor of their choice, while Group C, the control group, did not．This went on for a year of treatments．
By two months into the study, the patients in the laughter group had lower level of the hormones epinephrine （肾上腺素）, considered to cause stress, which is known to be deadly．After the 12 months, HDL cholesterol rises 26 percent in Group L but only 3 percent in Group           C．In another measure, C-reactive proteins, a maker of heart disease, drop 66 percent in the laughter group but only 26 percent in the control group．
“The best doctors believe that there is a physical good brought about by the positive emotion, happy laughter,” said study leader Lee Berk of Loma Linda University．And other research has found that humor makes us more hopeful．Still, more study is needed, Berk said．The research by Berk found that humor can bring about similar changes in body chemistry, which was proved in the new study．The research result will be presented this month at the meeting in the US．Research at the University of Maryland School of Medicine shows that laughter causes the inner lining of blood vessels to expand, increasing blood flow in a way thought to be healthy．
“Lifestyle choices have an important effect on health and these are choices which we and patients should pay attention to, rather than prevention and treatment,” Berk said in a statement this week．
Why did the scientists carry on the new research?

A．To find out if laughter was good to health．

B．To discover the best medicine to cure diabetes．

C．Because the number of diabetic patients is the largest in the world．

D．Because diabetic patients need more laughter than other patients．

After 12 months into the study, ___________．

A．C-reactive proteins increase 66 percent in Group C

B．the level of the hormones epinephrine stays the same in both groups

C．the level of the hormones epinephrine has dropped

D．C-reactive proteins reduced 66 percent in Group L

The underlined part “HDL cholesterol” in Paragraph 3 must be _______．

A．something bad to our health	B．something good to our health
C．a kind of wonderful medicine	D．a kind of dangerous disease

In what way does laughter benefit people’s health?

A．Blood is made thick by laughter．	B．Laughter makes blood vessels thin．
C．Laughter increases blood pressure．	D．Laughter makes blood flow fast．

According to Berk, we should _________．

A．choose lifestyles carefully	B．change our lifestyles
C．prevent our lifestyles in advance	D．pay less attention to the positive emotion