阅读理解。
There is an English saying, "Laughter is the best medicine." Until recently, few people took the saying
seriously. Now however, doctors have begun to look into laughter and the effects it has on the human body.
They have found that laughter really can improve people's health.
Tests were carried out to study the effects of laughter on the body. People watched funny films while
doctors checked their heart, blood pressure, breathing and muscles. It was found that laughter has similar
effects to physical exercise. It increases blood pressure, makes the heart beat quicker and makes people
breathe deeper; it also works several groups of muscles in the face, the stomach, and even the feet. If laughter
exercises the body, it must be beneficial.
Other tests have shown that laughter appears to be able to reduce the effect of pain on the body. In one
experiment doctors produced pain in groups of students who listened to different radio programmes. The
group that tolerated (忍耐) the pain for the longest time was the group which listened to a funny programme.
The reason why laughter can reduce pain seems to be that it helps to produce a kind of chemical in the brain
which diminishes both stress and pain.
As a result of these discoveries, some doctors in the United States now hold laughter clinics, in which they
help to improve their patients'condition by encouraging them to laugh. They have found that even if their
patients do not really feel like laughing, making them smile is enough to produce beneficial effects similar to
those caused by laughter.
1. Doctors have proved the following except that ________.
A. smiling does good to health
B. laughter can be tolerated
C. there is a way to reduce pain
D. laughter can work the muscles in the feet
2. The main idea of the passage is ________.
A. laughter and physical exercises have similar effects on the human body
B. smile can produce the same effects as laughter
C. pain can be reduced by laughter
D. laughter is best medicine
3. The underlined word"diminish" is similar to________.
A. test
B. stop
C. reduce
D. increase
4. Doctors hold laughter clinics _____.
A. to give better condition to their patients
B. in order to improve patients' health
C. to make patients smile
D. to prove smile and laughter have the same effect