There is an English saying, “_______” 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. ________
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.___ ___ 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 programs. The group that tolerated the pain for the longest time was the group which listened to a funny program. _______
______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.

A．Laughter can surely last one’s life.

B．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.

C．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.

D．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.

E. They have proved that laughter can really cure any disease if people keep a good state of mind.
F. Laughter is the best medicine.
G. They have found that laughter really can improve people’s health.