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 _  _ it has on the human body. They have found that laughter really can  _ _ people’s health.
Tests were carried out to study the effects of laughter on the body. People watched funny films __ __ doctors checked their heart, blood pressure, breathing and muscles. It was found that laughter has similar effects to     exercise.  It decreases blood pressure, the heart beat and breathing; it also works several groups of muscles in the face, the stomach, and even the feet. If laughter    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      pain in groups of students who listened to different radio programs. The group that tolerated the pain for the      time was the groups which listened to a funny program. The reason why laughter can reduce pain seems to be that it helps to produce a kind of chemicals in the brain which diminish( 减少 ) both stress and pain.
As a       of these discoveries, some doctors in the United States now hold laughter clinics, in which they help to improve their patients’ condition by   __ 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       to those caused by laughter.

A．harm B．strength C．effect D．good

A．help B．improve C．increase D．damage

A．if B．but C．while D．since

A．mental B．physical C．practical D．medical

A．guarantees B．applies C．maintains D．exercises

A．overlooked B．produced C．preserved D．ensured

A．remaining B．rest C．longest D．adequate

A．fact B．matter C．result D．sign

A．encouraging B．allowing C．assisting D．reminding

A．respectful B．subtle C．adaptable D．similar